Free webp to jpg
EN
Image MIME Reference
BMP

Windows Bitmap (Legacy Windows MIME Alias)

image/x-windows-bmp
VS

Microsoft Image Extension

image/vnd.mix
MIX

A complete technical comparison of Windows Bitmap (Legacy Windows MIME Alias) and Microsoft Image Extension — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.

BMP wins on browser support

Feature Support

Feature BMP MIX
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
Full BMP reference →
Microsoft Image Extension
image/vnd.mix
Extension
.mix
Container Microsoft OLE Structured Storage (COM)
Compression Proprietary (Internal JPEG/RLE)
Algorithm
JPEGDeflateProprietary
Color Depth 8-bit, 24-bit, 32-bit (RGBA)
Developed by Microsoft Corporation
Released 1996
Magic Bytes
D0 CF 11 E0 A1 B1 1A E1
Full MIX reference →

Browser Support Comparison

Browser BMP MIX
Chrome Chrome
✓ 1
 ✕
Firefox Firefox
✓ 1
 ✕
Safari Safari
✓ 1
 ✕
Edge Edge
✓ 12
 ✕
IE 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
MIX

MIX Strengths

  • Allowed early consumer software to non-destructively edit complex compositions involving photos, text, and vector clipart
  • Shared an architecture with other Microsoft Office products, enabling deep integration (OLE embedding) into Word and PowerPoint at the time
Limitations
  • Completely proprietary and undocumented, leading to a massive loss of historical data for users who archived their family photos in this project format
  • Requires traversing a complex OLE filesystem just to extract the flattened raster image
  • No support in modern image editors like Photoshop, GIMP, or web browsers

When to choose which format

BMP
Use BMP when…
  • Legacy Windows Desktop Registry Associations
  • Older Enterprise Intranet Applications
  • Windows Graphics Archival
MIX
Use MIX when…
  • Historical Microsoft Picture It! Projects
  • Microsoft PhotoDraw 2000 Graphics
  • Early 2000s Consumer Digital Scrapbooking

More comparisons

BMP vs ACES → MIX vs ACES → BMP vs APNG → MIX vs APNG → BMP vs AVCI → MIX vs AVCI → BMP vs AVCS → MIX vs AVCS → BMP vs AVIF → MIX vs AVIF → All comparisons →
Share this comparison