Free webp to jpg
Image MIME Reference
BMP

Windows Bitmap (Legacy Windows MIME Alias)

image/x-windows-bmp
VS

High Efficiency Image File Format

image/heif
HEIF

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

BMP wins on browser support

Feature Support

Feature BMP HEIF
Transparency (Alpha) Yes Yes
Animation Support ✕ No Yes
Progressive Loading ✕ No ✕ No
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
Full BMP reference →
High Efficiency Image File Format
image/heif
Extension
.heif.hif
Container HEIF / ISOBMFF (ISO/IEC 14496-12)
Compression Lossy / Lossless
Algorithm
Codec Agnostic (HEVC, AVC, JPEG, AV1)
Color Depth 8-bit, 10-bit, 12-bit, 16-bit
Developed by Moving Picture Experts Group (MPEG)
Released 2015
Magic Bytes
XX XX XX XX 66 74 79 70 6D 69 66 31
Full HEIF reference →

Browser Support Comparison

Browser BMP HEIF
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
HEIF

HEIF Strengths

  • Highly flexible container that can store image bursts, animations, focal stacks, and stereo 3D images in one file
  • Natively supports depth maps and alpha channels, making it perfect for computational photography
  • When paired with modern codecs like HEVC or AV1, it provides massive storage savings over legacy formats like JPEG
Limitations
  • Codec agnosticism makes broad software decoding difficult, as the container might hold proprietary or unsupported codecs
  • Zero cross-platform web browser support, requiring conversion for online publishing
  • Often confused with the more specific 'image/heic' and 'image/avif' MIME types

When to choose which format

BMP
Use BMP when…
  • Legacy Windows Desktop Registry Associations
  • Older Enterprise Intranet Applications
  • Windows Graphics Archival
HEIF
Use HEIF when…
  • Digital Photography
  • Camera Capture
  • Image Archiving
  • Multi-image composites
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