Image MIME Reference
BMP
Windows Bitmap (Legacy Windows MIME Alias)
image/x-windows-bmp
VS
TIFF for Facsimile eXtended
image/tiff-fx
TIFF-FX
A complete technical comparison of Windows Bitmap (Legacy Windows MIME Alias) and TIFF for Facsimile eXtended — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.
BMP wins on browser support
Feature Support
| Feature | BMP | TIFF-FX |
|---|---|---|
| Transparency (Alpha) | Yes | ✕ No |
| 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
TIFF for Facsimile eXtended
image/tiff-fx
Extension
.tiff.tif
Container
TIFF 6.0 Tag Directory Structure
Compression
MH / MR / MMR (CCITT Group 3 & 4) / JBIG / JPEG
Algorithm
CCITT Group 3/4JBIGJPEG
Color Depth
1-bit (Monochrome B&W), 8-bit (Grayscale/Color Indexed), 24-bit (RGB Color)
Developed by
IETF (Internet Engineering Task Force)
Released
1998
Magic Bytes
49 49 2A 00 (Little-Endian) / 4D 4D 00 2A (Big-Endian)
Browser Support Comparison
| Browser | BMP | TIFF-FX |
|---|---|---|
|
|
✓ 1
|
✕ |
|
|
✓ 1
|
✕ |
|
|
✓ 1
|
✕ |
|
|
✓ 12
|
✕ |
|
|
✓
|
✕ |
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
TIFF-FX
TIFF-FX Strengths
- Provides a universal, standardized format for transmitting multi-page documents over IP networks and email (Internet Fax)
- Supports highly efficient telecom-centric compression algorithms (MMR, JBIG) that produce very small files for text documents
- Maintains backwards compatibility with standard TIFF parsers
Limitations
- Not supported natively by web browsers
- Requires complex parsing of TIFF IFD tags to differentiate a true TIFF-FX file from a standard TIFF file
- Usage is slowly declining as traditional faxing is replaced by secure PDF transmission and e-signature platforms
When to choose which format
BMP
Use BMP when…
- Legacy Windows Desktop Registry Associations
- Older Enterprise Intranet Applications
- Windows Graphics Archival
TIFF-FX
Use TIFF-FX when…
- Internet Fax (T.37)
- Enterprise Fax Servers
- Document Archiving
- Telecommunications