Image MIME Reference
Alias-PIX
Alias PIX Image
image/x-alias-pix
VS
Digital Camera Raw (Generic Linux MIME)
image/x-dcraw
Generic-RAW
A complete technical comparison of Alias PIX Image and Digital Camera Raw (Generic Linux MIME) — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.
Equal browser support
Feature Support
| Feature | Alias-PIX | Generic-RAW |
|---|---|---|
| Transparency (Alpha) | ✕ No | ✕ No |
| Animation Support | ✕ No | ✕ No |
| Progressive Loading | ✕ No | ✕ No |
| HDR Support | ✕ No | Yes |
| EXIF Metadata | ✕ No | Yes |
| ICC Color Profile | ✕ No | Yes |
Alias PIX Image
image/x-alias-pix
Extension
.pix.als.alias.img
Container
Alias PIX Header
Compression
Run-Length Encoding (RLE)
Algorithm
RLE
Color Depth
24-bit (RGB), 8-bit (Matte/Grayscale variant)
Developed by
Alias Research (Later Alias|Wavefront / Autodesk)
Released
Early 1990s
Magic Bytes
No explicit magic bytes (Relies on 10-byte integer header)
Digital Camera Raw (Generic Linux MIME)
image/x-dcraw
Extension
.raw
Container
Varies (Predominantly TIFF/EP)
Compression
Lossless / Uncompressed
Algorithm
Varies (Often Lossless JPEG ITU-T81 or uncompressed)
Color Depth
12-bit, 14-bit, 16-bit
Developed by
freedesktop.org (MIME mapping) / Dave Coffin (dcraw tool)
Released
1997
Magic Bytes
Varies by vendor format
Browser Support Comparison
| Browser | Alias-PIX | Generic-RAW |
|---|---|---|
Chrome
|
✕ | ✕ |
Firefox
|
✕ | ✕ |
Safari
|
✕ | ✕ |
Edge
|
✕ | ✕ |
IE (Legacy)
|
✕ | ✕ |
Alias-PIX
Alias-PIX Strengths
- The highly simplified structure made it incredibly fast to encode and decode on early 1990s SGI hardware
- Lossless Run-Length Encoding (RLE) saved disk space without degrading the quality of final 3D renders
Limitations
- Completely obsolete, having been replaced by more robust formats like TIFF, TGA, and EXR in modern 3D pipelines
- The lack of a distinct magic byte signature makes reliable automated file detection almost impossible
- Does not support integrated alpha channels, instead requiring cumbersome, separate 'Matte' files to denote transparency
Generic-RAW
Generic-RAW Strengths
- Provides a unified, highly useful catch-all MIME type for application developers who just need to know if a file is a raw image, rather than tracking 50+ individual camera extensions
- Deeply integrated into the Linux desktop ecosystem, ensuring file manager thumbnails work seamlessly via tools like ufraw-thumbnailer
Limitations
- Not an official IANA standard
- Can cause conflicts where standard TIFF files are misidentified as raw camera data by over-aggressive MIME sniffers
- The underlying 'dcraw' tool was abandoned by its creator in 2018 (though its successor, LibRaw, continues to maintain the ecosystem)
When to choose which format
Alias-PIX
Use Alias-PIX when…
- Legacy Alias PowerAnimator Textures
- 1990s SGI Workstation Render Outputs
- Historical 3D Graphics Archival
Generic-RAW
Use Generic-RAW when…
- Linux Desktop File Associations (GNOME/KDE)
- Thumbnail Generation for Raw Images (UFRaw/LibRaw)
- Server-side Image Processing Fallbacks