Image MIME Reference
AIMG
Universal AI Media Format (Image)
image/prs.aimg
VS
JPEG 2000 Image Sequence (Obsolete)
image/hsj2
HSJ2
A complete technical comparison of Universal AI Media Format (Image) and JPEG 2000 Image Sequence (Obsolete) — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.
Equal browser support
Feature Support
| Feature | AIMG | HSJ2 |
|---|---|---|
| Transparency (Alpha) | Yes | Yes |
| Animation Support | Yes | Yes |
| Progressive Loading | ✕ No | Yes |
| HDR Support | Yes | Yes |
| EXIF Metadata | Yes | Yes |
| 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)
JPEG 2000 Image Sequence (Obsolete)
image/hsj2
Extension
.hsj2
Container
HEIF / ISOBMFF (ISO/IEC 15444-16 Obsolete)
Compression
Lossy / Lossless
Algorithm
Motion JPEG 2000 (ISO/IEC 15444-3)
Color Depth
8-bit, 10-bit, 12-bit, 16-bit
Developed by
ISO/IEC JTC 1 / ITU-T
Released
2019
Magic Bytes
XX XX XX XX 66 74 79 70 68 73 6A 32
Browser Support Comparison
| Browser | AIMG | HSJ2 |
|---|---|---|
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
HSJ2
HSJ2 Strengths
- Historically attempted to combine Motion JPEG 2000 sequences with the flexible metadata capabilities of the HEIF container
- Supported mathematically lossless compression and scalable wavelet decoding
Limitations
- Officially deprecated by the standardization body (ISO/IEC JTC 1)
- Completely superseded by image/hej2k, rendering hsj2 files obsolete for any new development or archiving
- Zero web browser compatibility and negligible modern software support
When to choose which format
AIMG
Use AIMG when…
- AI Provenance and Attribution
- Verifiable Deepfake Prevention
- Cryptographic Media Watermarking
- Generative AI Workflows
HSJ2
Use HSJ2 when…
- Legacy Archival
- Deprecated Workflows