Image MIME Reference
AIMG
Universal AI Media Format (Image)
image/prs.aimg
VS
Macromedia FreeHand Document
image/x-freehand
FreeHand
A complete technical comparison of Universal AI Media Format (Image) and Macromedia FreeHand Document — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.
Equal browser support
Feature Support
| Feature | AIMG | FreeHand |
|---|---|---|
| Transparency (Alpha) | Yes | Yes |
| Animation Support | Yes | Yes |
| Progressive Loading | ✕ No | ✕ No |
| HDR Support | Yes | ✕ No |
| EXIF Metadata | Yes | ✕ No |
| ICC Color Profile | Yes | Yes |
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)
Macromedia FreeHand Document
image/x-freehand
Extension
.fh.fh4.fh5.fh7.fh8.fh9.fh10.fh11.ft11
Container
Proprietary Binary (Aldus Graphic Document)
Compression
Uncompressed / Deflate (in later versions)
Algorithm
NoneDeflate (Optional in later versions)
Color Depth
Vector Data (RGB/CMYK)
Developed by
Altsys / Aldus / Macromedia
Released
1988
Magic Bytes
41 47 44 31 to 41 47 44 34
Browser Support Comparison
| Browser | AIMG | FreeHand |
|---|---|---|
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
FreeHand
FreeHand Strengths
- Historically one of the most powerful and intuitive vector editors on the market, praised for multi-page support long before Adobe Illustrator implemented it
- Files are generally compact and self-contained
Limitations
- Completely abandoned proprietary format; Adobe actively blocked native import in modern versions of Illustrator
- No support in modern web browsers; must be converted to SVG
- Versioning fragmentation means parsers must account for wildly different binary structures depending on the specific .fhX extension used
When to choose which format
AIMG
Use AIMG when…
- AI Provenance and Attribution
- Verifiable Deepfake Prevention
- Cryptographic Media Watermarking
- Generative AI Workflows
FreeHand
Use FreeHand when…
- Legacy Graphic Design Portfolios
- Historical Desktop Publishing Archival
- Old Corporate Logo Vectors