Image MIME Reference
AZV
AirZip Accelerator Image
image/vnd.airzip.accelerator.azv
VS
Microsoft Image Extension
image/vnd.mix
MIX
A complete technical comparison of AirZip Accelerator 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 | AZV | MIX |
|---|---|---|
| Transparency (Alpha) | ✕ No | Yes |
| Animation Support | ✕ No | ✕ No |
| Progressive Loading | Yes | ✕ No |
| HDR Support | ✕ No | ✕ No |
| EXIF Metadata | ✕ No | ✕ No |
| ICC Color Profile | ✕ No | Yes |
AirZip Accelerator Image
image/vnd.airzip.accelerator.azv
Extension
.azv
Container
Proprietary AirZip Container
Compression
Lossy (Proprietary) / Lossless (Proprietary)
Algorithm
AirZip Proprietary Compression
Color Depth
8-bit (Indexed), 24-bit (RGB)
Developed by
AirZip, Inc.
Released
1999
Magic Bytes
Unknown (Proprietary)
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 | AZV | MIX |
|---|---|---|
Chrome
|
✕ | ✕ |
Firefox
|
✕ | ✕ |
Safari
|
✕ | ✕ |
Edge
|
✕ | ✕ |
IE (Legacy)
|
✕ | ✕ |
AZV
AZV Strengths
- Historically allowed internet users to browse the web up to 5x faster over 56k dial-up modems by drastically reducing image payload sizes
- Officially registered in the IANA vendor tree, preventing MIME type conflicts on early web proxy servers
Limitations
- Completely obsolete in the modern broadband era
- Closed-source and proprietary, meaning no modern image manipulation libraries (like ImageMagick or libvips) can decode it
- Zero support in standard web browsers
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
AZV
Use AZV when…
- Dial-up Web Acceleration
- Bandwidth Optimization (Historical)
- Legacy Proxy Servers
MIX
Use MIX when…
- Historical Microsoft Picture It! Projects
- Microsoft PhotoDraw 2000 Graphics
- Early 2000s Consumer Digital Scrapbooking