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Image MIME Reference
JPM

JPEG 2000 Compound Image File Format

image/jpm
VS

Radiance HDR

image/vnd.radiance
Radiance

A complete technical comparison of JPEG 2000 Compound Image File Format and Radiance HDR — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.

Equal browser support

Feature Support

Feature JPM Radiance
Transparency (Alpha) Yes ✕ No
Animation Support ✕ No ✕ No
Progressive Loading Yes ✕ No
HDR Support ✕ No Yes
EXIF Metadata Yes ✕ No
ICC Color Profile Yes ✕ No
JPEG 2000 Compound Image File Format
image/jpm
Extension
.jpm.jpgm
Container ISOBMFF / JPM (ISO/IEC 15444-6)
Compression Lossy / Lossless / Mixed Raster Content (MRC)
Algorithm
JPEG 2000JBIG2JPEGMMR
Color Depth 1-bit (Text/Masks), 8-bit, 16-bit, 24-bit
Developed by Joint Photographic Experts Group (JPEG)
Released 2003
Magic Bytes
00 00 00 0C 6A 50 20 20 0D 0A 87 0A ... 66 74 79 70 6A 70 6D 20
Full JPM reference →
Radiance HDR
image/vnd.radiance
Extension
.hdr.pic.rgbe.xyze
Container Radiance Information Header
Compression Run-Length Encoding (RLE) / Uncompressed
Algorithm
Adaptive Run-Length Encoding (RLE)
Color Depth 32-bit (8-bit per channel RGB + 8-bit shared Exponent)
Developed by Greg Ward (Lawrence Berkeley National Laboratory)
Released 1989
Magic Bytes
23 3F 52 41 44 49 41 4E 43 45
Full Radiance reference →

Browser Support Comparison

Browser JPM Radiance
Chrome Chrome
✕ ✕
Firefox Firefox
✕ ✕
Safari Safari
✕ ✕
Edge Edge
✕ ✕
IE IE (Legacy)
✕ ✕
JPM

JPM Strengths

  • Highly optimized for scanned documents, drastically reducing file sizes without sacrificing the readability of text or the quality of embedded photos
  • Supports multi-page documents within a single file
  • Object-based architecture allows for complex layout representation and independent extraction of elements
Limitations
  • Failed to achieve widespread adoption, largely being overshadowed by PDF/A and DjVu
  • Zero native web browser compatibility
  • Requires complex, specialized software to properly encode and decode the multi-layered MRC structure
Radiance

Radiance Strengths

  • Universally supported by almost every 3D modeling software, renderer, and game engine in existence
  • RGBE encoding offers a brilliant balance between High Dynamic Range capability and small file size (compared to 32-bit float OpenEXR)
  • Simple, easy-to-parse ASCII header followed by straightforward RLE binary data
Limitations
  • Does not support alpha transparency (no way to store an isolated light source with a transparent background)
  • The shared exponent architecture can occasionally introduce banding or color artifacts in extreme edge cases compared to true 16-bit/32-bit floating-point formats like OpenEXR
  • Zero native browser support for 2D viewing

When to choose which format

JPM
Use JPM when…
  • Scanned Document Archiving
  • Mixed Raster Content (MRC) Imaging
  • Digital Libraries
Radiance
Use Radiance when…
  • Image-Based Lighting (IBL)
  • 3D Environment Maps (HDRI Skydomes)
  • Lighting Simulation
  • VFX and CGI Rendering

More comparisons

JPM vs ACES → Radiance vs ACES → JPM vs APNG → Radiance vs APNG → JPM vs AVCI → Radiance vs AVCI → JPM vs AVCS → Radiance vs AVCS → JPM vs AVIF → Radiance vs AVIF → All comparisons →
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