Free webp to jpg
Image MIME Reference
JPM

JPEG 2000 Compound Image File Format

image/jpm
VS

Windows Metafile

image/x-wmf
WMF

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

Equal browser support

Feature Support

Feature JPM WMF
Transparency (Alpha) Yes Yes
Animation Support ✕ No ✕ No
Progressive Loading Yes ✕ No
HDR Support ✕ No ✕ No
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 →
Windows Metafile
image/x-wmf
Extension
.wmf.emf
Container Windows GDI Metafile Command Stream
Compression Uncompressed (Command Stream)
Algorithm
None
Color Depth Varies based on GDI rendering engine
Developed by Microsoft Corporation
Released 1990
Magic Bytes
D7 CD C6 9A (Aldus Placeable Metafile Header) or 01 00 09 00 (Standard WMF Header)
Full WMF reference →

Browser Support Comparison

Browser JPM WMF
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
WMF

WMF Strengths

  • Infinitely scalable vector format that remains remarkably compact for simple geometric illustrations and charts
  • Historically served as a seamless conduit for copying and pasting vector graphics between disparate Windows applications via the system clipboard
Limitations
  • Notoriously plagued by historic security vulnerabilities, making raw WMF parsing a vector for exploits in legacy software
  • Completely obsolete and unsupported in modern web environments (browsers cannot render them)
  • Strictly tied to the Windows GDI architecture, making cross-platform rendering inconsistent across Linux and macOS

When to choose which format

JPM
Use JPM when…
  • Scanned Document Archiving
  • Mixed Raster Content (MRC) Imaging
  • Digital Libraries
WMF
Use WMF when…
  • Legacy Microsoft Office Clip Art and Icons
  • Windows GDI Graphics Export
  • Early Windows Desktop Publishing
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