Image MIME Reference
MIX
Microsoft Image Extension
image/vnd.mix
VS
X Window Dump (Legacy MIME Alias)
image/x-xwindowdump
XWD
A complete technical comparison of Microsoft Image Extension and X Window Dump (Legacy MIME Alias) — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.
Equal browser support
Feature Support
| Feature | MIX | XWD |
|---|---|---|
| Transparency (Alpha) | Yes | Yes |
| Animation Support | ✕ No | ✕ No |
| Progressive Loading | ✕ No | ✕ No |
| HDR Support | ✕ No | ✕ No |
| EXIF Metadata | ✕ No | ✕ No |
| ICC Color Profile | Yes | ✕ No |
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
X Window Dump (Legacy MIME Alias)
image/x-xwindowdump
Extension
.xwd.wd
Container
XWDHeader / XWDFileHeader Structure
Compression
Uncompressed
Algorithm
None
Color Depth
8-bit (Indexed), 16-bit (High Color), 24-bit (True Color), 32-bit (True Color with Alpha/Padding)
Developed by
MIT / X Consortium (X Window System)
Released
1987
Magic Bytes
00 00 00 64 (Typically indicates a 100-byte header size followed by version)
Browser Support Comparison
| Browser | MIX | XWD |
|---|---|---|
Chrome
|
✕ | ✕ |
Firefox
|
✕ | ✕ |
Safari
|
✕ | ✕ |
Edge
|
✕ | ✕ |
IE (Legacy)
|
✕ | ✕ |
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
XWD
XWD Strengths
- Provides an exact, raw pixel dump directly from the X11 display server memory without compression overhead
- Extremely fast for Unix environments to generate during low-level graphical debugging
Limitations
- Completely uncompressed, resulting in large, bloated file sizes
- Zero support in web browsers or modern desktop environments without specialized graphics translation tools
- Verbose legacy MIME strings like 'image/x-xwindowdump' require backend normalization in modern applications
When to choose which format
MIX
Use MIX when…
- Historical Microsoft Picture It! Projects
- Microsoft PhotoDraw 2000 Graphics
- Early 2000s Consumer Digital Scrapbooking
XWD
Use XWD when…
- X Window System (X11) Display Debugging and Screenshots
- Legacy Unix/Linux System Administration