Image MIME Reference
CGM
Computer Graphics Metafile
image/cgm
VS
GIMP Image Format
image/x-xcf
XCF
A complete technical comparison of Computer Graphics Metafile and GIMP Image Format — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.
Equal browser support
Feature Support
| Feature | CGM | XCF |
|---|---|---|
| Transparency (Alpha) | Yes | Yes |
| Animation Support | ✕ No | Yes |
| Progressive Loading | ✕ No | ✕ No |
| HDR Support | ✕ No | Yes |
| EXIF Metadata | ✕ No | Yes |
| ICC Color Profile | Yes | Yes |
Computer Graphics Metafile
image/cgm
Extension
.cgm
Container
CGM
Compression
Uncompressed / Binary / Character / Clear Text
Algorithm
Deflate (in some WebCGM profiles)
Color Depth
8-bit, 16-bit, 24-bit, 32-bit
Developed by
ISO / IEC
Released
1987
Magic Bytes
00 20 (Binary) / 42 45 47 49 4E 20 4D 45 54 41 46 49 4C 45 (Clear Text)
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 | CGM | XCF |
|---|---|---|
Chrome
|
✕ | ✕ |
Firefox
|
✕ | ✕ |
Safari
|
✕ | ✕ |
Edge
|
✕ | ✕ |
IE (Legacy)
|
✕ | ✕ |
CGM
CGM Strengths
- Strictly standardized by ISO, ensuring long-term archiving and cross-platform compatibility in engineering
- Excellent support for rich metadata, hyperlinks, and technical hotspots via the WebCGM profile
- Can store complex 2D geometry, rasters, and text in a single lightweight file
Limitations
- Multiple encoding schemes (Binary, Character, Clear Text) make parser development difficult
- Zero native support in modern web browsers without third-party plugins
- Largely replaced by SVG for general-purpose 2D vector graphics on the web
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
CGM
Use CGM when…
- Technical Illustrations
- Aerospace & Defense (S1000D)
- CAD/CAM
- Geophysics
XCF
Use XCF when…
- GIMP Native Project Archival
- Layered Photo Editing and Graphic Design
- Intermediary Asset Preparation for Export