Image MIME Reference
AZV
AirZip Accelerator Image
image/vnd.airzip.accelerator.azv
VS
GIMP Image Format
image/x-xcf
XCF
A complete technical comparison of AirZip Accelerator Image and GIMP Image Format — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.
Equal browser support
Feature Support
| Feature | AZV | XCF |
|---|---|---|
| Transparency (Alpha) | ✕ No | Yes |
| Animation Support | ✕ No | Yes |
| Progressive Loading | Yes | ✕ No |
| HDR Support | ✕ No | Yes |
| EXIF Metadata | ✕ No | Yes |
| 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)
GIMP Image Format
image/x-xcf
Extension
.xcf
Container
GIMP Hierarchical Chunk Container
Compression
None / RLE (Run-Length Encoding) / Zlib / Deflate (In newer GIMP versions)
Algorithm
NoneRLEZlib
Color Depth
8-bit per channel, 16-bit per channel, 32-bit floating point
Developed by
Spencer Kimball, Peter Mattis, and the GIMP Development Team
Released
1995
Magic Bytes
67 69 6D 70 20 78 63 66
Browser Support Comparison
| Browser | AZV | XCF |
|---|---|---|
|
|
✕ | ✕ |
|
|
✕ | ✕ |
|
|
✕ | ✕ |
|
|
✕ | ✕ |
|
|
✕ | ✕ |
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
XCF
XCF Strengths
- Preserves all non-destructive editing elements, layer hierarchies, masks, and alpha channels across GIMP sessions
- Open and thoroughly documented specification within the open-source community, allowing third-party tools like Krita and ImageMagick to read project files
- Reliable magic byte header prevents misidentification
Limitations
- Massive file sizes because raw, unflattened layer bitmaps and masks are stored directly within the project archive
- Completely proprietary to the GIMP ecosystem for deep editing; cannot be natively rendered or parsed by web browsers
- Third-party software supporting XCF may occasionally struggle to render complex text layer adjustments or advanced layer blend modes identically to GIMP
When to choose which format
AZV
Use AZV when…
- Dial-up Web Acceleration
- Bandwidth Optimization (Historical)
- Legacy Proxy Servers
XCF
Use XCF when…
- GIMP Native Project Archival
- Layered Photo Editing and Graphic Design
- Intermediary Asset Preparation for Export