Image MIME Reference
CGM
Computer Graphics Metafile
image/cgm
VS
PCO B16 Image
image/vnd.pco.b16
PCO-B16
A complete technical comparison of Computer Graphics Metafile and PCO B16 Image — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.
Equal browser support
Feature Support
| Feature | CGM | PCO-B16 |
|---|---|---|
| Transparency (Alpha) | Yes | ✕ No |
| Animation Support | ✕ No | ✕ No |
| Progressive Loading | ✕ No | ✕ No |
| HDR Support | ✕ No | ✕ No |
| EXIF Metadata | ✕ No | ✕ No |
| ICC Color Profile | Yes | ✕ No |
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)
PCO B16 Image
image/vnd.pco.b16
Extension
.b16
Container
PCO B16 Binary Container
Compression
Uncompressed (Raw Sensor Data)
Algorithm
None
Color Depth
16-bit (Monochrome or Bayer Raw Color)
Developed by
PCO AG (Excelitas PCO GmbH)
Released
Early 2000s
Magic Bytes
50 43 4F 2D
Browser Support Comparison
| Browser | CGM | PCO-B16 |
|---|---|---|
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
PCO-B16
PCO-B16 Strengths
- Preserves exact, uncompressed 16-bit raw sensor data, which is critically important for accurate scientific measurements, fluorescence microscopy, and photometry
- The simple, linear struct header is highly predictable and easy to parse in custom Python, MATLAB, or C++ scripts for researchers building bespoke pipelines
Limitations
- Generates massive file sizes due to the complete lack of image compression [1.3.1]
- Completely unsupported by standard operating systems, web browsers, and consumer image editing suites
- Strictly tied to the hardware and software ecosystems of a single camera manufacturer
When to choose which format
CGM
Use CGM when…
- Technical Illustrations
- Aerospace & Defense (S1000D)
- CAD/CAM
- Geophysics
PCO-B16
Use PCO-B16 when…
- Microscopy and Life Sciences
- High-Speed Camera Recording
- Machine Vision and Industrial Inspection
- Scientific Photometry