Image MIME Reference
MODI
Microsoft Document Imaging
image/vnd.ms-modi
VS
X Pixmap
image/x-xpixmap
XPM
A complete technical comparison of Microsoft Document Imaging and X Pixmap — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.
Equal browser support
Feature Support
| Feature | MODI | XPM |
|---|---|---|
| Transparency (Alpha) | ✕ No | Yes |
| Animation Support | ✕ No | ✕ No |
| Progressive Loading | ✕ No | ✕ No |
| HDR Support | ✕ No | ✕ No |
| EXIF Metadata | ✕ No | ✕ No |
| ICC Color Profile | ✕ No | ✕ No |
Microsoft Document Imaging
image/vnd.ms-modi
Extension
.mdi
Container
TIFF Variant
Compression
LZW / Proprietary MS Compression
Algorithm
LZW (Modified)
Color Depth
1-bit (Monochrome), 8-bit (Grayscale), 24-bit (RGB)
Developed by
Microsoft Corporation
Released
2001
Magic Bytes
49 49 2A 00
X Pixmap
image/x-xpixmap
Extension
.xpm
Container
C Source Code Header (.c / .h)
Compression
Uncompressed (Source Code)
Algorithm
None
Color Depth
Indexed Color (Custom Palette with RGB and Alpha 'None')
Developed by
Daniel Dardailler and Colas Nahaboo (Bull / X Consortium)
Released
1989
Magic Bytes
2F 2A 20 58 50 4D 20 2A 2F (ASCII '/* XPM */')
Browser Support Comparison
| Browser | MODI | XPM |
|---|---|---|
Chrome
|
✕ | ✕ |
Firefox
|
✕ | ✕ |
Safari
|
✕ | ✕ |
Edge
|
✕ | ✕ |
IE (Legacy)
|
✕ |
✓
|
MODI
MODI Strengths
- Historically provided an excellent all-in-one scanned document format with built-in OCR and annotations before PDF editing became universally accessible
- Tightly integrated with Microsoft Office and SharePoint workflows in the early 2000s
Limitations
- Completely proprietary and obsolete; Microsoft abandoned it in favor of standard TIFF and PDF
- Causes widespread identification conflicts since its file signature is identical to a standard TIFF
- Extremely difficult to open on modern operating systems without relying on third-party conversion utilities
XPM
XPM Strengths
- Can be compiled directly into C or C++ source code without requiring an external asset loading mechanism
- Human-readable palette mapping allows developers to inspect, modify, or hand-craft icons directly within a text editor
- Native support for color palettes and transparency via the 'None' keyword
Limitations
- Extremely inefficient storage structure for large images, resulting in massive file bloat compared to binary formats like PNG
- Completely obsolete and unsupported in modern web browsers
- Parsing overhead requires compiling or interpreting text-based color tables at runtime
When to choose which format
MODI
Use MODI when…
- Legacy Scanned Document Archival
- Microsoft Office XP/2003/2007 Workflows
- Embedded OCR Text Storage
XPM
Use XPM when…
- X Window System (X11) Application Icons and Cursors
- Embedded C/C++ Firmware Color UI Assets
- Early Linux Desktop Environment Themes