Image MIME Reference
TIFF-FX
TIFF for Facsimile eXtended
image/tiff-fx
VS
X Pixmap
image/x-xpixmap
XPM
A complete technical comparison of TIFF for Facsimile eXtended and X Pixmap — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.
Equal browser support
Feature Support
| Feature | TIFF-FX | XPM |
|---|---|---|
| Transparency (Alpha) | ✕ No | Yes |
| Animation Support | ✕ No | ✕ No |
| Progressive Loading | ✕ No | ✕ No |
| HDR Support | ✕ No | ✕ No |
| EXIF Metadata | ✕ No | ✕ No |
| ICC Color Profile | Yes | ✕ No |
TIFF for Facsimile eXtended
image/tiff-fx
Extension
.tiff.tif
Container
TIFF 6.0 Tag Directory Structure
Compression
MH / MR / MMR (CCITT Group 3 & 4) / JBIG / JPEG
Algorithm
CCITT Group 3/4JBIGJPEG
Color Depth
1-bit (Monochrome B&W), 8-bit (Grayscale/Color Indexed), 24-bit (RGB Color)
Developed by
IETF (Internet Engineering Task Force)
Released
1998
Magic Bytes
49 49 2A 00 (Little-Endian) / 4D 4D 00 2A (Big-Endian)
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 | TIFF-FX | XPM |
|---|---|---|
|
|
✕ | ✕ |
|
|
✕ | ✕ |
|
|
✕ | ✕ |
|
|
✕ | ✕ |
|
|
✕ |
✓
|
TIFF-FX
TIFF-FX Strengths
- Provides a universal, standardized format for transmitting multi-page documents over IP networks and email (Internet Fax)
- Supports highly efficient telecom-centric compression algorithms (MMR, JBIG) that produce very small files for text documents
- Maintains backwards compatibility with standard TIFF parsers
Limitations
- Not supported natively by web browsers
- Requires complex parsing of TIFF IFD tags to differentiate a true TIFF-FX file from a standard TIFF file
- Usage is slowly declining as traditional faxing is replaced by secure PDF transmission and e-signature platforms
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
TIFF-FX
Use TIFF-FX when…
- Internet Fax (T.37)
- Enterprise Fax Servers
- Document Archiving
- Telecommunications
XPM
Use XPM when…
- X Window System (X11) Application Icons and Cursors
- Embedded C/C++ Firmware Color UI Assets
- Early Linux Desktop Environment Themes