Image MIME Reference
CGM
Computer Graphics Metafile
image/cgm
VS
PaintShop Pro Image
image/x-paintshoppro
PaintShop-Pro-PSP
A complete technical comparison of Computer Graphics Metafile and PaintShop Pro Image — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.
Equal browser support
Feature Support
| Feature | CGM | PaintShop-Pro-PSP |
|---|---|---|
| Transparency (Alpha) | Yes | Yes |
| Animation Support | ✕ No | ✕ No |
| 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)
PaintShop Pro Image
image/x-paintshoppro
Extension
.psp.pspimage.tub.pat
Container
PSP Chunk-based Format
Compression
Uncompressed / RLE (Run-Length Encoding) / LZ77
Algorithm
RLELZ77
Color Depth
8-bit (Indexed), 16-bit (Grayscale), 24-bit (RGB), 32-bit (RGBA), 48-bit (High Color)
Developed by
Jasc Software / Corel Corporation (Alludo)
Released
1990
Magic Bytes
7E 42 4B 00
Browser Support Comparison
| Browser | CGM | PaintShop-Pro-PSP |
|---|---|---|
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✕ | ✕ |
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✕ | ✕ |
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✕ | ✕ |
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✕ | ✕ |
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✕ | ✕ |
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
PaintShop-Pro-PSP
PaintShop-Pro-PSP Strengths
- Provides robust, non-destructive editing capabilities with full support for vector layers, adjustment layers, and layer blend modes
- Historically offered a highly capable and affordable alternative to Adobe Photoshop's PSD format for Windows users
- Features proprietary support for 'Picture Tubes' (.tub), a unique brush technology that paints sequential or random raster objects along a path
Limitations
- Deeply proprietary format tied exclusively to the Corel/Alludo ecosystem
- Third-party software support (like GIMP or ImageMagick) is often limited to parsing older .psp files, frequently failing to render complex layers in modern .pspimage files
- No support in modern web browsers; must be exported to a flattened web format (JPEG/PNG) for online viewing
When to choose which format
CGM
Use CGM when…
- Technical Illustrations
- Aerospace & Defense (S1000D)
- CAD/CAM
- Geophysics
PaintShop-Pro-PSP
Use PaintShop-Pro-PSP when…
- PaintShop Pro Multi-layer Project Archival
- Digital Art and Photo Retouching
- Picture Tubes (.tub) and Custom Patterns (.pat)