Image MIME Reference
BMP
Windows Bitmap (Legacy Windows MIME Alias)
image/x-windows-bmp
VS
JPEG XR Image (HEIF Container)
image/jxra
JPEG-XR-(HEIF)
A complete technical comparison of Windows Bitmap (Legacy Windows MIME Alias) and JPEG XR Image (HEIF Container) — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.
BMP wins on browser support
Feature Support
| Feature | BMP | JPEG-XR-(HEIF) |
|---|---|---|
| Transparency (Alpha) | Yes | Yes |
| Animation Support | ✕ No | ✕ No |
| Progressive Loading | ✕ No | Yes |
| HDR Support | ✕ No | Yes |
| EXIF Metadata | ✕ No | Yes |
| 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
JPEG XR Image (HEIF Container)
image/jxra
Extension
.jxra
Container
HEIF / ISOBMFF (ISO/IEC 23008-12 / Annex F of ITU-T T.832)
Compression
Lossy / Lossless
Algorithm
JPEG XR (Lapped Biorthogonal Transform)
Color Depth
8-bit, 16-bit, 32-bit (Float)
Developed by
ISO/IEC JTC 1 / ITU-T
Released
2019
Magic Bytes
XX XX XX XX 66 74 79 70 6A 78 72 41
Browser Support Comparison
| Browser | BMP | JPEG-XR-(HEIF) |
|---|---|---|
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
JPEG-XR-(HEIF)
JPEG-XR-(HEIF) Strengths
- Combines the deep color (32-bit float) and mathematically lossless compression of JPEG XR with the robust metadata architecture of HEIF
- Allows grouping multiple images, exposure brackets, or focal stacks into a single file collection
Limitations
- Practically non-existent software and operating system support compared to standard HEIC or legacy JPEG XR (.jxr)
- Zero web browser support, rendering it entirely unsuitable for public web deployment
- Eclipsed by modern standards like AVIF and JPEG XL which offer superior compression with much broader industry backing
When to choose which format
BMP
Use BMP when…
- Legacy Windows Desktop Registry Associations
- Older Enterprise Intranet Applications
- Windows Graphics Archival
JPEG-XR-(HEIF)
Use JPEG-XR-(HEIF) when…
- Specialized Archival
- Experimental Imaging Workflows
- High Dynamic Range (HDR) Imaging