Image MIME Reference
BMP
Windows Bitmap (Legacy Windows MIME Alias)
image/x-windows-bmp
VS
Corel Metafile Exchange
image/x-cmx
Corel-CMX
A complete technical comparison of Windows Bitmap (Legacy Windows MIME Alias) and Corel Metafile Exchange — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.
BMP wins on browser support
Feature Support
| Feature | BMP | Corel-CMX |
|---|---|---|
| Transparency (Alpha) | Yes | Yes |
| Animation Support | ✕ No | ✕ No |
| Progressive Loading | ✕ No | ✕ No |
| HDR Support | ✕ No | ✕ No |
| EXIF Metadata | ✕ No | ✕ No |
| ICC Color Profile | Yes | Yes |
Windows Bitmap (Legacy Windows MIME Alias)
image/x-windows-bmp
Extension
.bmp.dib
Container
DIB (Device-Independent Bitmap)
Compression
Uncompressed / Run-Length Encoding (RLE)
Algorithm
NoneRLE4RLE8
Color Depth
1-bit (Monochrome), 4-bit (16 colors), 8-bit (256 colors), 16-bit (High Color), 24-bit (True Color), 32-bit (True Color with Alpha)
Developed by
Microsoft Corporation
Released
1985
Magic Bytes
42 4D
Corel Metafile Exchange
image/x-cmx
Extension
.cmx
Container
RIFF (Resource Interchange File Format)
Compression
Uncompressed Vector Commands / Embedded Raster Compression (Optional)
Algorithm
None (Vector)
Color Depth
Vector Data, Supports embedded bitmaps
Developed by
Corel Corporation
Released
Mid-1990s
Magic Bytes
52 49 46 46 (skip 4) 43 4D 58 31
Browser Support Comparison
| Browser | BMP | Corel-CMX |
|---|---|---|
Chrome
|
✓ 1
|
✕ |
Firefox
|
✓ 1
|
✕ |
Safari
|
✓ 1
|
✕ |
Edge
|
✓ 12
|
✕ |
IE (Legacy)
|
✓
|
✕ |
BMP
BMP Strengths
- Universally supported by all major operating systems and modern web browsers
- Maintains perfect, lossless fidelity because pixel data is stored without lossy compression artifacts
Limitations
- Massive file size overhead due to a lack of modern compression algorithms
- Legacy MIME strings like 'image/x-windows-bmp' can trigger validation warnings in strict security or API environments if unhandled
Corel-CMX
Corel-CMX Strengths
- Preserves rich vector attributes and layer groupings native to the Corel drawing engine better than standard WMF files
- Significantly smaller footprint than full CDR project files, making it excellent for early CD-ROM clip art distribution
- Maintains decent support in the open-source community thanks to libraries like libcdr
Limitations
- Proprietary format strictly tied to Corel's ecosystem, often causing compatibility issues with Adobe software
- Zero support in web browsers; must be converted to SVG for modern web usage
- Largely obsolete for modern workflows, superseded by PDF and SVG
When to choose which format
BMP
Use BMP when…
- Legacy Windows Desktop Registry Associations
- Older Enterprise Intranet Applications
- Windows Graphics Archival
Corel-CMX
Use Corel-CMX when…
- Legacy CorelDRAW Clip Art Collections
- Vector Graphic Exchange within Corel Suite
- Historical Desktop Publishing Assets