Image MIME Reference
FACTI
BlockFact Image
image/vnd.blockfact.facti
VS
JPEG XR Image (HEIF Container)
image/jxra
JPEG-XR-(HEIF)
A complete technical comparison of BlockFact Image and JPEG XR Image (HEIF Container) — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.
Equal browser support
Feature Support
| Feature | FACTI | JPEG-XR-(HEIF) |
|---|---|---|
| Transparency (Alpha) | Yes | Yes |
| Animation Support | ✕ No | ✕ No |
| Progressive Loading | ✕ No | Yes |
| HDR Support | Yes | Yes |
| EXIF Metadata | Yes | Yes |
| ICC Color Profile | Yes | Yes |
BlockFact Image
image/vnd.blockfact.facti
Extension
.facti
Container
BlockFact Authenticated Container
Compression
Container (Inherits payload compression, e.g., JPEG/PNG)
Algorithm
None (Pass-through to embedded payload)
Color Depth
Inherited from payload
Developed by
BlockFact
Released
2025
Magic Bytes
Unknown (Proprietary Container)
JPEG XR Image (HEIF Container)
image/jxra
Extension
.jxra
Container
HEIF / ISOBMFF (ISO/IEC 23008-12 / Annex F of ITU-T T.832)
Compression
Lossy / Lossless
Algorithm
JPEG XR (Lapped Biorthogonal Transform)
Color Depth
8-bit, 16-bit, 32-bit (Float)
Developed by
ISO/IEC JTC 1 / ITU-T
Released
2019
Magic Bytes
XX XX XX XX 66 74 79 70 6A 78 72 41
Browser Support Comparison
| Browser | FACTI | JPEG-XR-(HEIF) |
|---|---|---|
Chrome
|
✕ | ✕ |
Firefox
|
✕ | ✕ |
Safari
|
✕ | ✕ |
Edge
|
✕ | ✕ |
IE (Legacy)
|
✕ | ✕ |
FACTI
FACTI Strengths
- Provides undeniable, mathematically verifiable proof of a photo's origin (time, location, and device) via the StarkNet blockchain [1.3.1]
- Privacy-first design utilizes zero-knowledge proofs (Groth16), meaning the actual image is never uploaded to a central server or blockchain
- Invisible watermarking ensures that even if the image is screenshotted or cropped, tampering can be detected
Limitations
- Lacks native rendering support in web browsers and standard image viewers, requiring specialized software to view
- Requires blockchain registration at the moment of capture, making it incompatible with existing legacy photos
- The proprietary nature of the container limits integration to environments supporting the BlockFact SDK
JPEG-XR-(HEIF)
JPEG-XR-(HEIF) Strengths
- Combines the deep color (32-bit float) and mathematically lossless compression of JPEG XR with the robust metadata architecture of HEIF
- Allows grouping multiple images, exposure brackets, or focal stacks into a single file collection
Limitations
- Practically non-existent software and operating system support compared to standard HEIC or legacy JPEG XR (.jxr)
- Zero web browser support, rendering it entirely unsuitable for public web deployment
- Eclipsed by modern standards like AVIF and JPEG XL which offer superior compression with much broader industry backing
When to choose which format
FACTI
Use FACTI when…
- Journalism and Media Authentication
- Legal and Insurance Evidence
- AI Deepfake Prevention
- Content Provenance and Authorship
JPEG-XR-(HEIF)
Use JPEG-XR-(HEIF) when…
- Specialized Archival
- Experimental Imaging Workflows
- High Dynamic Range (HDR) Imaging