Image MIME Reference
FACTI
BlockFact Image
image/vnd.blockfact.facti
VS
Microsoft Image Extension
image/vnd.mix
MIX
A complete technical comparison of BlockFact Image and Microsoft Image Extension — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.
Equal browser support
Feature Support
| Feature | FACTI | MIX |
|---|---|---|
| Transparency (Alpha) | Yes | Yes |
| Animation Support | ✕ No | ✕ No |
| Progressive Loading | ✕ No | ✕ No |
| HDR Support | Yes | ✕ No |
| EXIF Metadata | Yes | ✕ No |
| 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)
Microsoft Image Extension
image/vnd.mix
Extension
.mix
Container
Microsoft OLE Structured Storage (COM)
Compression
Proprietary (Internal JPEG/RLE)
Algorithm
JPEGDeflateProprietary
Color Depth
8-bit, 24-bit, 32-bit (RGBA)
Developed by
Microsoft Corporation
Released
1996
Magic Bytes
D0 CF 11 E0 A1 B1 1A E1
Browser Support Comparison
| Browser | FACTI | MIX |
|---|---|---|
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
MIX
MIX Strengths
- Allowed early consumer software to non-destructively edit complex compositions involving photos, text, and vector clipart
- Shared an architecture with other Microsoft Office products, enabling deep integration (OLE embedding) into Word and PowerPoint at the time
Limitations
- Completely proprietary and undocumented, leading to a massive loss of historical data for users who archived their family photos in this project format
- Requires traversing a complex OLE filesystem just to extract the flattened raster image
- No support in modern image editors like Photoshop, GIMP, or web browsers
When to choose which format
FACTI
Use FACTI when…
- Journalism and Media Authentication
- Legal and Insurance Evidence
- AI Deepfake Prevention
- Content Provenance and Authorship
MIX
Use MIX when…
- Historical Microsoft Picture It! Projects
- Microsoft PhotoDraw 2000 Graphics
- Early 2000s Consumer Digital Scrapbooking