Image MIME Reference
AIMG
Universal AI Media Format (Image)
image/prs.aimg
VS
CMU Window Manager Raster
image/x-cmu-raster
CMU-Raster
A complete technical comparison of Universal AI Media Format (Image) and CMU Window Manager Raster — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.
Equal browser support
Feature Support
| Feature | AIMG | CMU-Raster |
|---|---|---|
| Transparency (Alpha) | Yes | ✕ No |
| Animation Support | Yes | ✕ No |
| Progressive Loading | ✕ No | ✕ No |
| HDR Support | Yes | ✕ No |
| EXIF Metadata | Yes | ✕ No |
| ICC Color Profile | Yes | ✕ No |
Universal AI Media Format (Image)
image/prs.aimg
Extension
.aimg
Container
Universal AI Media Format (AIMF)
Compression
Container (Inherits payload compression, e.g., PNG/JPEG)
Algorithm
None (Pass-through to embedded payload)
Color Depth
Inherited from payload (8-bit, 16-bit, HDR)
Developed by
AI Media Format (ai-mf) Open-Source Project
Released
2026
Magic Bytes
Varies (Custom AIMF Header Prepended to Payload)
CMU Window Manager Raster
image/x-cmu-raster
Extension
.ras
Container
CMU Window Manager Bitmap
Compression
Uncompressed
Algorithm
None
Color Depth
1-bit (Monochrome), 8-bit (Indexed/Grayscale)
Developed by
Carnegie Mellon University (CMU)
Released
1980s
Magic Bytes
F1 00 40 BB
Browser Support Comparison
| Browser | AIMG | CMU-Raster |
|---|---|---|
Chrome
|
✕ | ✕ |
Firefox
|
✕ | ✕ |
Safari
|
✕ | ✕ |
Edge
|
✕ | ✕ |
IE (Legacy)
|
✕ | ✕ |
AIMG
AIMG Strengths
- Provides a robust, tamper-evident cryptographic wrapper to definitively prove the origin of AI-generated media
- Header-first structure allows verifier nodes and APIs to validate an image's origin without needing to download or decode the entire massive pixel payload
Limitations
- Lacks native rendering support in browsers, requiring server-side extraction or client-side WebAssembly to display the embedded image
- Utilizes the IANA 'prs.' (personal/vanity) tree rather than the standards tree, which can cause strict enterprise firewalls to reject the MIME type as unverified
CMU-Raster
CMU-Raster Strengths
- Incredibly simple, uncompressed binary structure that was easy for early, memory-constrained UNIX workstations to parse and render
Limitations
- Completely obsolete and unsupported outside of niche historical command-line tools like Netpbm
- The shared '.ras' file extension causes frequent file misidentification and system conflicts
- Lacks all modern imaging features, including metadata, compression, and alpha channel transparency
When to choose which format
AIMG
Use AIMG when…
- AI Provenance and Attribution
- Verifiable Deepfake Prevention
- Cryptographic Media Watermarking
- Generative AI Workflows
CMU-Raster
Use CMU-Raster when…
- Historical UNIX / Andrew Project Archival
- Legacy Academic Computing Research