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Supported Formats
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Web Formats
Joint Photographic Experts Group - the most universal image format for photographs using lossy compression. Reduces file sizes 90-95% with minimal visible quality loss. No transparency support. Perfect for photos, web images, email attachments, and any scenario requiring small file sizes. Adjustable quality levels from 1-100. Standard since 1992 with universal device and software support. Ideal for photographs and complex images with many colors.
Portable Network Graphics - lossless image format supporting transparency and 16 million colors. Larger files than JPEG but perfect quality preservation. Supports alpha channel for smooth transparency. Excellent for logos, graphics with text, screenshots, and images requiring transparency. Better compression than GIF for photos. Perfect for web graphics, UI elements, and any image needing lossless quality or transparency. Standard format for web graphics since 1996.
Web Picture format - modern image format by Google providing 25-35% smaller files than JPEG at equivalent quality. Supports both lossy and lossless compression plus transparency. Superior compression algorithms reducing bandwidth usage. Native browser support (96%+ coverage). Perfect for website optimization, web images, and reducing page load times. Combines best features of JPEG, PNG, and GIF. Recommended for modern web development.
Graphics Interchange Format - image format supporting animation and transparency with 256-color limitation. Small file sizes for simple images. Perfect for simple animations, emojis, memes, and graphics with few colors. Lossless for limited palette. Inefficient for photographs (use JPEG) or high-color graphics (use PNG). Universal support since 1987. Standard format for simple web animations and reaction images.
Scalable Vector Graphics - XML-based vector format rendering perfectly at any size. Infinitely scalable without quality loss or pixelation. Small file sizes for geometric shapes and illustrations. Editable with text editors and design software. Perfect for logos, icons, diagrams, and graphics requiring scaling. Supports animation and interactivity. Standard for responsive web graphics and resolution-independent designs. Essential format for modern web icons.
Icon File Format - specialized format for Windows icons containing multiple image sizes (16x16 to 256x256 pixels). Single file provides icons for all display resolutions. Used for favicons, application icons, and Windows shell icons. Supports transparency and multiple color depths. Perfect for website favicons, Windows program icons, and shortcut icons. Standard format for Windows icons since Windows 1.0. Essential for professional Windows applications.
AV1 Image File Format - next-generation image format based on AV1 video codec providing better compression than WebP and JPEG. 20-50% smaller files at equivalent quality. Supports HDR, wide color gamut, and transparency. Cutting-edge compression technology. Growing browser support (85%+ and increasing). Perfect for future-proof web images and maximum efficiency. Better quality at smaller sizes than any previous format. Recommended for modern websites prioritizing performance.
Bitmap Image File - uncompressed raster format from Microsoft providing pixel-perfect quality with large file sizes. No compression means huge files (1MB+ for screenshots). Fast to load and display. Simple format with universal Windows support. Perfect for temporary graphics, screen captures, and scenarios where compression artifacts are unacceptable. Legacy format largely replaced by PNG. Convert to PNG or JPEG for practical use and storage.
Tagged Image File Format - flexible format supporting multiple pages, layers, and various compression methods. Industry standard for professional photography, publishing, and archival. Supports lossless compression, 16-bit color depth, and extensive metadata. Large file sizes but excellent quality. Perfect for print publishing, photo archival, professional photography, and scenarios requiring maximum quality and flexibility. Used in medical imaging and professional scanning.
Professional Formats
Photoshop Document - Adobe Photoshop's native format preserving layers, effects, masks, and all editing capabilities. Supports 16-bit and 32-bit color depths for professional work. Large file sizes due to layer data and editing information. Perfect for ongoing design projects, professional photo editing, and collaborative design work. Not suitable for final output (export to JPEG/PNG). Essential format for professional graphic design and photo manipulation workflows. Industry standard for design files.
OpenEXR - high dynamic range image format developed by Industrial Light & Magic for visual effects and animation. Stores 16-bit or 32-bit floating-point values per channel enabling enormous dynamic range. Supports multiple layers, arbitrary channels, and lossless/lossy compression. Industry standard for VFX, CGI, and professional 3D rendering. Perfect for HDR photography, compositing, and scenarios requiring maximum color precision. Used extensively in film production and high-end visual effects.
High Dynamic Range Image - format storing luminance and color information with greater range than standard images. Captures and displays brightness levels impossible in JPEG/PNG. Uses 32-bit floating-point encoding. Perfect for realistic lighting in 3D rendering, environment maps, and HDR photography. Common in game development and architectural visualization. Enables realistic tone mapping and exposure adjustment. Essential for professional lighting workflows.
DirectDraw Surface - Microsoft texture format for games and 3D applications supporting compressed textures and mipmaps. Optimized for GPU loading with hardware-accelerated decompression. Stores multiple resolution levels (mipmaps) in single file. Standard format for game textures (DirectX, Unity, Unreal). Supports various compression algorithms (DXT1, DXT5, BC7). Perfect for game development, 3D modeling, and real-time rendering. Essential format for game asset pipelines.
Truevision TGA/Targa - raster graphics format supporting 8-32 bits per pixel with alpha channel. Uncompressed or RLE compressed for fast loading. Standard format for video editing, animation, and texture mapping. Excellent color accuracy with optional lossless compression. Perfect for video frame sequences, animation frames, and game textures. Widely supported in 3D software and video editing applications. Reliable format for professional media production.
JPEG 2000 - advanced image format using wavelet compression providing better quality than JPEG at equivalent file sizes. Supports lossless and lossy compression, progressive decoding, and ROI coding. Used in medical imaging, digital cinema, and archival. Better compression artifacts than JPEG. Slower encoding/decoding. Perfect for medical imaging, digital preservation, and applications requiring superior compression. Limited web browser support.
JPEG Stereo - stereoscopic 3D image format storing left and right eye views side-by-side or top-bottom. Based on standard JPEG with special arrangement for 3D viewing. Used for 3D photography, VR content, and stereoscopic displays. Compatible with 3D TVs and VR headsets. Perfect for 3D photography, stereoscopic content creation, and VR/AR applications. Requires special viewing equipment for proper 3D effect.
Portable Float Map - floating-point image format storing HDR color data. Simple format with 32-bit float values per channel. Used in computer graphics for HDR images and height maps. Uncompressed format with large file sizes. Perfect for HDR photography processing, displacement maps, and scientific imaging. Common in 3D rendering and simulation applications. Alternative to OpenEXR for simple HDR storage.
Flexible Image Transport System - scientific image format used primarily in astronomy. Stores astronomical images with extensive metadata headers. Supports multiple data arrays and tables. Standard format for astronomical data archives. Perfect for astronomical imaging, scientific data exchange, and research applications. Used by major observatories and space agencies worldwide. Essential format for astronomical research and data sharing.
Mobile Formats
High Efficiency Image Container - Apple's modern image format using HEVC compression providing 50% smaller files than JPEG at equivalent quality. Default format for iOS photos since iOS 11. Supports HDR, transparency, and image sequences. Excellent quality with tiny file sizes. Limited compatibility outside Apple ecosystem. Convert to JPEG for broad sharing. Perfect for iOS photography and Apple device storage optimization. Future-oriented format gaining broader support.
High Efficiency Image Format - container format using HEVC or other compression methods. More versatile than HEIC supporting various codecs. Supports image sequences, burst photos, and depth maps. Used by Apple devices and modern cameras. Better compression than JPEG with smaller file sizes. Perfect for modern photography, image sequences, and efficient storage. Growing support across platforms and devices.
Joint Photographic Experts Group - standard JPEG variant with .jpeg extension instead of .jpg. Identical format and capabilities to JPG files. Same lossy compression and universal compatibility. Used interchangeably with .jpg extension. Perfect for all scenarios where JPG is appropriate. No technical difference from JPG format. Extension preference varies by platform and tradition.
JPEG Image - alternative JPEG file extension used less commonly than .jpg or .jpeg. Identical format and compression to standard JPEG. Full compatibility with all JPEG-supporting software. Occasionally used by older Windows systems. Perfect for any JPEG use case. Convert to .jpg for broader recognition. No technical differences from standard JPEG format.
JPEG File Interchange Format - JPEG variant with specific structure for data exchange. Standard way to encode JPEG for maximum compatibility. Includes specific header markers and color space definitions. Ensures consistent JPEG interpretation across platforms. Perfect for reliable JPEG exchange and archival. Most JPEGs actually use JFIF structure. Technical specification ensuring JPEG interoperability.
JPEG File Interchange - alternative extension for JFIF-compliant JPEG files. Same format and capabilities as standard JPEG/JFIF. Used occasionally by specific software and systems. Perfect compatibility with all JPEG viewers. Perfect for any JPEG application. Consider using .jpg for better recognition. Functionally identical to standard JPEG format.
JPEG Interchange Format - another extension variant for JPEG images. Identical compression and structure to standard JPEG. Full compatibility with JPEG software. Rarely used compared to .jpg extension. Perfect for standard JPEG use cases. Rename to .jpg for universal recognition. No technical distinction from regular JPEG files.
Raw Formats
Raw RGB - uncompressed raw red-green-blue color data without headers or metadata. Pure pixel data requiring width/height specification for viewing. Maximum quality with enormous file sizes. Used in image processing pipelines and professional workflows. Perfect for image processing intermediates, scientific imaging, and maximum quality requirements. Requires external dimension information. Essential for professional image manipulation workflows.
Raw RGBA - uncompressed RGB data with alpha channel for transparency. Four channels (red, green, blue, alpha) without compression. Requires dimension specification for proper viewing. Huge file sizes due to no compression. Perfect for image processing with transparency, compositing workflows, and professional graphics. Used in video production and game development. Maximum quality preservation with alpha information.
RGB with Opacity - variant of RGB format including opacity/transparency information. Uncompressed pixel data with alpha channel. Used in specific graphics workflows and professional software. Requires external dimension data. Perfect for professional compositing, graphics production, and transparency workflows. Alternative to RGBA in some applications. Maintains maximum quality with transparency.
Raw Graphics Format - uncompressed raw image data used in specific professional workflows. Simple binary format without metadata headers. Requires dimension and color space information for proper viewing. Used in specialized imaging applications and scientific software. Perfect for image processing pipelines, scientific imaging, and professional graphics workflows. Maximum quality with minimal file structure.
YUV Color Space - raw format storing luminance (Y) and chrominance (U, V) separately. Used extensively in video processing and broadcast. More efficient than RGB for human vision. Common in video codecs and professional video equipment. Perfect for video frame extraction, broadcast workflows, and video processing. Essential format in television and video production. Enables efficient compression in video codecs.
UYVY Color Format - packed YUV format with specific byte ordering (U, Y, V, Y). Common in video capture and professional video equipment. Interleaved chroma and luma for efficient processing. Used by video capture cards and cameras. Perfect for video frame processing, capture workflows, and broadcast applications. Standard format in professional video equipment. Optimized for hardware video processing.
Unix Formats
X PixMap - ASCII-based image format for X Window System icons. Human-readable C source code format. Simple format for small icons and cursors. Used primarily on Unix/Linux systems. Perfect for X Window icons, cursors, and small graphics on Unix systems. Can be compiled directly into programs. Legacy format still found in Linux applications.
X BitMap - monochrome bitmap format for X Window System. ASCII format representing black and white images. Used for cursors, icons, and simple graphics on Unix/Linux. Very small file sizes for 1-bit images. Perfect for X Window cursors, monochrome icons, and simple Unix graphics. C language header file format. Historic Unix/Linux bitmap format.
X Window Dump - screen capture format for X Window System. Stores complete window or screen contents with color information. Native X11 format for screenshots and window captures. Includes X server-specific information. Perfect for X Window screenshots, Unix screen captures, and X11 debugging. Used primarily on Unix/Linux systems. Standard screenshot format for X-based systems.
XV Thumbnail - image format for XV image viewer on Unix systems. Used for thumbnail caches and quick previews. Simple format optimized for fast loading. Associated with the xv image viewer application. Perfect for XV image viewer thumbnails and Unix image browsing. Legacy format from classic Unix graphics software. Found in older Unix image management systems.
Sun Raster - image format from Sun Microsystems for SunOS and Solaris systems. Supports various color depths and compression methods. Standard format on Sun workstations and servers. Used extensively in scientific and engineering applications on Sun systems. Perfect for legacy Sun system compatibility and Solaris applications. Historical importance in Unix workstation graphics. Convert to modern formats for current use.
Silicon Graphics Image - professional image format from SGI workstations. Supports RGB and RGBA with RLE compression. Used extensively in computer graphics and visual effects. Standard format on SGI/IRIX systems. Perfect for legacy SGI compatibility, professional graphics workflows, and film production archives. Historical significance in 3D graphics evolution. Used in early CGI and digital effects.
Sun Raster Image - another extension for Sun Raster format. Same capabilities as .sun format. Used on Sun Microsystems systems and Solaris. Supports various color depths and optional RLE compression. Perfect for Sun/Solaris compatibility and legacy system support. Alternative extension to .sun files. Convert to modern formats for broader compatibility.
Portable Formats
Portable PixMap - simple uncompressed RGB format from Netpbm suite. Human-readable ASCII or binary format. Maximum portability across platforms. No compression leading to large files. Perfect for image processing intermediates, Unix graphics workflows, and maximum portability. Part of portable pixmap family. Extremely simple format ensuring universal compatibility.
Portable BitMap - monochrome format from Netpbm suite. ASCII or binary format for black and white images. Simplest possible image format. Perfect for monochrome graphics, fax images, and simple bitmap data. Extremely portable and easy to generate programmatically. Part of Netpbm image family. Used in document scanning and OCR workflows.
Portable GrayMap - grayscale format from Netpbm suite. ASCII or binary format for grayscale images. Simple structure ensuring maximum portability. No compression. Perfect for grayscale photography, scientific imaging, and image processing. Part of portable pixmap family. Used extensively in image processing education and research.
Portable Any Map - generic format encompassing PBM, PGM, and PPM. Automatically handles monochrome, grayscale, or color images. Most flexible Netpbm format. Perfect for general-purpose portable image storage and Unix graphics workflows. Universal format in Unix image processing. Enables format-agnostic image handling.
Portable Arbitrary Map - extended Netpbm format supporting alpha channels and arbitrary color depths. More capable than PBM/PGM/PPM with similar simplicity. Supports transparency and high bit depths. Perfect for modern portable image workflows with transparency. Extended Netpbm format for contemporary needs. Maintains Netpbm simplicity with modern features.
Legacy Formats
PC Paintbrush - legacy DOS graphics format from ZSoft Corporation. Standard image format in DOS era (1980s-1990s). Supports various color depths and RLE compression. Common in early Windows applications. Perfect for DOS/early Windows compatibility and retro computing. Historical importance in PC graphics evolution. Convert to modern formats for current use.
Apple Picture - legacy Macintosh graphics format (Mac OS Classic). Supported both bitmap and vector graphics. Native format for Classic Mac applications. Obsolete with Mac OS X transition. Perfect for recovering images from vintage Mac systems. Historical format important for Mac archive access. Convert to modern formats for usability.
PICT Image - alternative extension for Apple PICT format. Same capabilities as .pict files. Used on Macintosh systems before Mac OS X. Supports bitmap and vector data. Perfect for Classic Mac compatibility and vintage system recovery. Alternative extension to .pict. Legacy format requiring conversion for modern use.
Kodak Photo CD - proprietary format for Kodak Photo CD system. Stores images at multiple resolutions in single file. Used by Kodak for photo scanning and archival services. Includes multiple resolution layers for different uses. Perfect for Photo CD archive access and Kodak imaging system compatibility. Legacy professional photography format. Historical importance in digital photography transition.
Palm Database Image - Palm OS format for storing images on Palm PDAs. Compressed format optimized for small devices. Used on Palm Pilot and related handhelds. Legacy format from PDA era (1990s-2000s). Perfect for Palm device compatibility and vintage PDA recovery. Historical format from handheld computing. Convert to modern formats for accessibility.
Palm Pixmap - bitmap format for Palm OS devices. Optimized for Palm handheld screens and memory limitations. Simple format with limited color depths. Used on Palm PDAs and early smartphones. Perfect for Palm OS compatibility and retro PDA applications. Legacy format from handheld era. Important for Palm device emulation and archival.
Windows Cursor - format for Windows mouse cursor images. Contains hotspot information defining click point. May include multiple sizes for different resolutions. Used for custom cursors in Windows applications. Perfect for Windows cursor design, custom mouse pointers, and UI development. Standard format for Windows cursors since Windows 1.0. Essential for Windows UI customization.
Specialized Formats
VIPS Image - format for libvips image processing library. Supports large images and streaming operations. Optimized for efficient memory usage with huge images. Used in image processing pipelines and server-side imaging. Perfect for processing large images, batch operations, and memory-efficient workflows. Essential for server-side image processing. Specialized format for libvips ecosystem.
Visualization Image File Format - image format for Khoros visualization software. Supports various data types and multi-dimensional images. Used in scientific visualization and image processing research. Includes extensive metadata capabilities. Perfect for scientific imaging, visualization workflows, and research applications. Specialized format for Khoros system. Used in academic image processing.
Multiple-image Network Graphics - animated image format related to PNG. Supports animation with better compression than GIF. PNG-based animation format with advanced features. Limited browser support compared to GIF. Perfect for complex animations with transparency. Better quality than animated GIF. Superseded by APNG and WebP for most uses.
MTV Raytracer - image format for MTV raytracing software. Simple format for raytraced images. Used by MTV raytracer program on Unix systems. Academic and research format from computer graphics education. Perfect for MTV raytracer compatibility and computer graphics education. Specialized format from raytracing software. Legacy format from graphics research.
Wireless Bitmap - monochrome format for early mobile phones and wireless devices. Optimized for limited bandwidth and memory. Used in WAP (Wireless Application Protocol) era. Tiny file sizes for 1-bit images. Perfect for legacy mobile device compatibility. Historical format from early mobile web. Obsolete with modern smartphones.
JPEG 2000 Reference - format for JPEG 2000 development and testing. Simple format for individual image components. Used in JPEG 2000 codec development and testing. Perfect for JPEG 2000 research, codec testing, and format development. Specialized format for image compression research. Used in academic and standards work.
Palette File - color palette/colormap format used by various graphics software. Stores color lookup tables for indexed images. Used with indexed color images and sprite graphics. Perfect for game development, pixel art workflows, and indexed color management. Common in retro game development. Essential for palette-based graphics.
Colormap - another palette format storing color lookup tables. Used by various graphics applications for indexed colors. Defines available colors for indexed images. Perfect for indexed color workflows, game development, and palette management. Common in graphics software and game development tools. Used with palette-based image formats.
Fax & Print Formats
Fax Image - format for fax machine documents. Monochrome format optimized for text documents. Uses efficient compression for black and white pages. Standard format for fax transmission and storage. Perfect for fax document archival, legacy fax system compatibility, and document scanning. Used in telecommunications and document management. Essential for fax machine compatibility.
CCITT Group 3 Fax - standard fax compression format (one-dimensional). Efficient compression for black and white documents. Standard for fax transmission worldwide. One-dimensional compression algorithm. Perfect for fax documents, scanned text pages, and telecommunications. Used in virtually all fax machines. Essential standard for fax communication.
CCITT Group 4 Fax - advanced fax compression format (two-dimensional). Better compression than G3 for text documents. Higher quality fax transmission. Two-dimensional compression for superior efficiency. Perfect for high-quality fax, document archival, and scanning workflows. Recommended fax format for quality and file size. Standard for modern fax systems.
JBIG - bilevel image compression standard for high-resolution black and white images. Superior compression to G3/G4 fax formats. Used in document scanning and archival. Progressive coding enabling resolution scaling. Perfect for high-resolution document scanning, archival imaging, and efficient black and white compression. Successor to G3/G4. Used in professional document management.
JBIG Image - alternative extension for JBIG compressed images. Same capabilities as .jbg format. Efficient bilevel compression for documents. Used in document imaging and scanning applications. Perfect for high-quality document compression, scanning workflows, and archival systems. Alternative extension to .jbg files. Professional document imaging format.
Retro Formats
Sixel Graphics - bitmap format for DEC terminals and printers. Uses six-pixel vertical slices encoded as characters. Historic format from DEC terminal era (1970s-1980s). Enabled graphics on text-only terminals. Perfect for terminal graphics, retro computing, and DEC system compatibility. Legacy format with nostalgic significance. Used in terminal emulators for retro graphics.
SIX Format - alternative extension for Sixel graphics. Same capabilities as .sixel format. DEC terminal graphics format. Used for graphics on VT terminals. Perfect for DEC terminal compatibility and vintage system emulation. Alternative extension to .sixel files. Historical format from terminal graphics era.
Slow Scan TV - format for amateur radio slow-scan television. Transmits images over radio frequencies. Used in amateur radio for image transmission. Simple format optimized for radio transmission. Perfect for ham radio SSTV applications and radio image exchange. Specialized format for radio amateurs. Important in amateur radio communication.
IPLab Image - format for IPLab image analysis software. Used in scientific image processing and analysis. Supports various data types and metadata. Common in microscopy and scientific imaging. Perfect for IPLab software compatibility, scientific image analysis, and microscopy workflows. Specialized format for image analysis software. Used in scientific research.
Personal Icon - small icon format for email and newsgroups. 48x48 pixel images representing people in directories. Used in academic and early internet systems. Perfect for personal icon databases and vintage internet systems. Historical format from early internet era. Legacy format for academic systems.
On-the-air Bitmap - format for Nokia phones and wireless devices. Used in mobile phone applications and services. Simple bitmap format for limited devices. Perfect for Nokia device compatibility and vintage mobile applications. Legacy format from early mobile phones. Historical format from pre-smartphone era.
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Frequently Asked Questions
What is a SIX file and where did this obscure format come from?
A SIX file is a simple bitmap image format associated primarily with early Unix environments, vintage graphics toolkits, and certain niche software packages that stored uncompressed raster graphics in a minimal header-plus-pixel-array structure. The format is extremely bare-bones, usually containing little more than width, height, and raw pixel data arranged in a strict linear order. Because of its simplicity, SIX files were easy to load, easy to parse, and ideal for systems with extremely limited computing power or primitive graphics stacks.
Most SIX images came from proprietary or application-specific toolchains rather than a single standardized specification. This is why programs today may interpret SIX images differently depending on their origin—some use indexed color, some grayscale, and others raw RGB. The format never achieved mainstream adoption, but it remains relevant in legacy workflows, retro-computing, Unix archival data sets, and research material preserved from the 80s and 90s.
How is a SIX file structured internally?
Because SIX came from multiple toolsets, structure varies slightly, but most SIX files follow a predictable minimal layout:
Minimal Header
A tiny header normally provides width, height, and sometimes color mode. Many SIX variants store dimensions as plain integers at the beginning of the file.
Raw Pixel Stream
After the header, pixel data is usually raw and uncompressed—either grayscale bytes, indexed palette references, or direct RGB triples.
No Metadata Block
There is no embedded metadata, no EXIF, no ICC profile, no color calibration—SIX is strictly a raster dump.
Consistent Row Ordering
Pixels are stored row-by-row, top to bottom, making decoding straightforward for low-level graphics APIs.
Because the structure is minimal, SIX files load extremely fast and can be parsed by even the simplest binary readers.
Where are SIX files still used today?
SIX files appear in several niche and legacy environments:
Old Unix Graphics Pipelines
Early imaging tools generated SIX files because they were simple to implement and easy to process with C libraries.
Retro Computing Research
Hobbyists exploring archival X11, SunView, or experimental toolkits often encounter SIX files.
Custom Scientific Devices
Older laboratory equipment output SIX raster dumps because the format required almost zero processing.
Legacy Printing Systems
Some early printers or framebuffer utilities converted raw bitmaps into SIX containers for compatibility.
Digital Preservation Projects
Long-term data archives sometimes hold SIX images preserved from discontinued Unix software.
Niche Proprietary Tooling
Some specialized engineering or CAD tools from the 90s exported SIX because it guaranteed predictable decoding.
Embedded and Low-Memory Hardware
SIX works in extremely memory-limited environments because it has no compression overhead.
Even though it is obscure today, SIX remains valuable in situations where absolute simplicity matters.
Why are SIX files low-quality compared to modern image formats?
Most SIX variants use no compression and have limited color options, often restricted to grayscale or small palettes.
Raw pixel dumps lack features like chroma subsampling, dithering, gamma correction, or advanced tone mapping.
Many SIX tools were built for monochrome displays or low-resolution hardware, so the files reflect that limitation.
How does SIX compare to portable image formats like PNG or JPEG?
SIX lacks compression—PNG and JPEG dramatically reduce size using advanced algorithms while SIX remains bulky.
SIX offers no metadata, no transparency, and no color management, whereas PNG and JPEG include rich ancillary data.
Its only advantage is simplicity—SIX loads instantly and can be decoded by extremely small programs.
Does SIX support color, transparency, or alpha channels?
Some implementations support RGB, but many only store grayscale or indexed palettes depending on the original toolkit.
Transparency is not supported in any classic SIX variant.
Bit depth is typically 8-bit per channel or lower, making SIX unsuitable for high-fidelity graphics.
Why do many converters fail to open SIX files?
There is no universal SIX standard—different software produced different SIX variants.
Some SIX files include unusual header structures or assume application-specific color palettes.
Modern image libraries do not prioritize compatibility with obscure legacy formats.
Why do SIX conversions sometimes break or distort?
Conversion problems typically result from ambiguity in the format:
Unknown Header Layout
Width and height may be stored in a non-standard order or in unusual integer formats.
Palette Ambiguity
Indexed SIX images may rely on an external palette no longer available.
Missing Color Information
Some SIX dumps contain only raw pixel bytes without explaining the color model.
Row Alignment Issues
Certain SIX files align rows on fixed boundaries, causing shifted or wrapped images when parsed incorrectly.
Truncated Pixel Dumps
Legacy systems sometimes output incomplete raster streams, resulting in corrupted images when converted.
Using tools that support multiple SIX variants improves decoding reliability.
Does SIX support embedded metadata?
No—SIX includes no EXIF, ICC profiles, timestamps, or geodata.
It is strictly a bitmap container with no descriptive blocks.
Any contextual information must be stored separately.
What are the modern use cases for SIX today?
Despite its age, SIX still remains relevant in specific contexts:
Archival Restoration
Preservation teams often need to decode SIX files embedded in old Unix software archives.
Scientific Legacy Systems
Certain research machines still output SIX images for compatibility with decades-old analysis tools.
Embedded Firmware
Microcontrollers use SIX-style dumps because they can be parsed easily with minimal code.
Vintage Hardware
Retro terminals and early workstations sometimes store screenshots in SIX format.
Unix Graphics Infrastructure
SIX is still supported by some ImageMagick builds and legacy conversion utilities.
Debugging and Pixel Dumping
Developers use SIX as a quick way to dump framebuffers during debugging.
Proprietary Historic Software
Specialized engineering tools from the 90s exported SIX because the decoder could be implemented in a few lines of C.
Low-Level Benchmarking
SIX files are useful for testing raw pixel throughput in experimental rendering pipelines.
Conversion Research
Format researchers analyze SIX to understand early raster workflow evolution.
Art and Retro Graphics
Enthusiasts sometimes use SIX for stylistic retro rendering or terminal-bound graphics demos.
Why are SIX files sometimes extremely large?
Without compression, every pixel requires full byte representation.
RGB SIX variants triple file size by storing separate red, green, and blue channels.
High resolutions produce disproportionately large files compared to PNG or JPEG.
How big can SIX files get before they cause issues?
Large SIX files may exceed memory limits of older tools that assume small rasters.
Some decoders cannot handle wide images because they expect rows under fixed byte limits.
Terminal-based viewers struggle with very large SIX dumps due to lack of scaling features.
Can SIX store multiple frames or pages?
No—SIX is strictly a single-image raster format.
Multi-frame behavior must be simulated with multiple separate SIX files.
Some early tools chained SIX frames manually for animations, but each remained an independent image.
Why do some SIX images appear rotated or inverted?
Some variants store pixel rows bottom-up rather than top-down.
Others insert alignment padding that shifts pixel rows when interpreted incorrectly.
Because the format was never standardized, orientation inconsistencies are common.
Is the SIX format still relevant today?
While obsolete for mainstream imaging, SIX remains important in fields involving legacy systems and digital preservation.
Its ultra-simple design makes it ideal for embedded debugging, raw framebuffer dumps, and retro workflows.
For modern imaging tasks, SIX is not competitive—but in specialized environments, its minimalism is still an advantage.