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Image MIME Reference
JPM

JPEG 2000 Compound Image File Format

image/jpm
VS

JPEG 2000 Part 2 (Extended)

image/jpx
JPX

A complete technical comparison of JPEG 2000 Compound Image File Format and JPEG 2000 Part 2 (Extended) — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.

Equal browser support

Feature Support

Feature JPM JPX
Transparency (Alpha) Yes Yes
Animation Support ✕ No Yes
Progressive Loading Yes Yes
HDR Support ✕ No Yes
EXIF Metadata Yes Yes
ICC Color Profile Yes Yes
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 →
JPEG 2000 Part 2 (Extended)
image/jpx
Extension
.jpx.jpf
Container ISOBMFF / JPX (ISO/IEC 15444-2)
Compression Lossy / Lossless
Algorithm
Discrete Wavelet Transform (DWT)
Color Depth 8-bit, 16-bit, 32-bit, 38-bit
Developed by Joint Photographic Experts Group (JPEG)
Released 2002
Magic Bytes
00 00 00 0C 6A 50 20 20 0D 0A 87 0A ... 66 74 79 70 6A 70 78 20
Full JPX reference →

Browser Support Comparison

Browser JPM JPX
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
JPX

JPX Strengths

  • Removes the color space limitations of baseline JP2, adding native support for CMYK, CIE Lab, and custom vendor color spaces
  • Supports multiple codestreams in a single file, allowing for rich compositing and animation
  • Enables fragmented files where image data and metadata can reside in separate physical files via data references
Limitations
  • Extremely complex specification makes full software implementation rare, leading to compatibility issues
  • Zero web browser support, rendering it unsuitable for public internet distribution
  • Often overkill for standard imaging tasks where baseline JP2 or modern alternatives like AVIF suffice

When to choose which format

JPM
Use JPM when…
  • Scanned Document Archiving
  • Mixed Raster Content (MRC) Imaging
  • Digital Libraries
JPX
Use JPX when…
  • Prepress & Commercial Printing (CMYK)
  • Geospatial Data
  • Archival Preservation
  • Medical Imaging

More comparisons

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