Image MIME Reference
Net-FPX
Network FlashPix
image/vnd.net-fpx
VS
X Pixmap
image/x-xpixmap
XPM
A complete technical comparison of Network FlashPix and X Pixmap — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.
Equal browser support
Feature Support
| Feature | Net-FPX | XPM |
|---|---|---|
| Transparency (Alpha) | Yes | Yes |
| Animation Support | ✕ No | ✕ No |
| Progressive Loading | Yes | ✕ No |
| HDR Support | ✕ No | ✕ No |
| EXIF Metadata | Yes | ✕ No |
| ICC Color Profile | Yes | ✕ No |
Network FlashPix
image/vnd.net-fpx
Extension
.fpx
Container
Microsoft OLE Structured Storage (COM)
Compression
JPEG (Lossy) / Uncompressed / Single-color (Solid)
Algorithm
JPEGNone
Color Depth
8-bit (Grayscale/Indexed), 24-bit (RGB), 32-bit (CMYK/RGBA)
Developed by
Digital Imaging Group (Kodak, HP, Live Picture, Microsoft)
Released
1996
Magic Bytes
D0 CF 11 E0 A1 B1 1A E1
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 | Net-FPX | XPM |
|---|---|---|
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|
✕ | ✕ |
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|
✕ | ✕ |
|
|
✕ | ✕ |
|
|
✕ | ✕ |
|
|
✕ |
✓
|
Net-FPX
Net-FPX Strengths
- Revolutionized web imaging in the late 1990s by proving that massive gigapixel images could be navigated seamlessly over 56k dial-up modems
- Pioneered the tile-based, multi-resolution pyramid concepts that eventually evolved into modern standards like IIIF (International Image Interoperability Framework)
Limitations
- Completely obsolete, having been replaced by standard JPEG servers and modern tiling formats like Deep Zoom or JPEG 2000/XR
- Relied on proprietary Java applets or ActiveX controls to render the tiles dynamically in a web browser
- Extremely complex to parse server-side due to the heavy OLE filesystem container
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
Net-FPX
Use Net-FPX when…
- Historical Internet Imaging Protocol (IIP) Streaming
- Early E-Commerce Deep Zoom Implementations
- Legacy High-Resolution Image Servers
XPM
Use XPM when…
- X Window System (X11) Application Icons and Cursors
- Embedded C/C++ Firmware Color UI Assets
- Early Linux Desktop Environment Themes