Image MIME Reference
JPEG-2000
JPEG 2000 Core Image File
image/jp2
VS
Windows Metafile
image/x-wmf
WMF
A complete technical comparison of JPEG 2000 Core Image File and Windows Metafile — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.
JPEG-2000 wins on browser support
Feature Support
| Feature | JPEG-2000 | WMF |
|---|---|---|
| Transparency (Alpha) | Yes | Yes |
| Animation Support | ✕ No | ✕ No |
| Progressive Loading | Yes | ✕ No |
| HDR Support | Yes | ✕ No |
| EXIF Metadata | Yes | ✕ No |
| ICC Color Profile | Yes | ✕ No |
JPEG 2000 Core Image File
image/jp2
Extension
.jp2.j2k.jpf.jpx.jpm
Container
JP2 (ISO/IEC 15444-1)
Compression
Lossy / Lossless
Algorithm
Discrete Wavelet Transform (DWT)
Color Depth
8-bit, 16-bit, 32-bit, 38-bit
Developed by
Joint Photographic Experts Group
Released
2000
Magic Bytes
00 00 00 0C 6A 50 20 20 0D 0A 87 0A
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)
Browser Support Comparison
| Browser | JPEG-2000 | WMF |
|---|---|---|
Chrome
|
✕ | ✕ |
Firefox
|
✕ | ✕ |
Safari
|
✓ 5+
|
✕ |
Edge
|
✕ | ✕ |
IE (Legacy)
|
✕ |
✓
|
JPEG-2000
JPEG-2000 Strengths
- Superior compression efficiency over baseline JPEG without introducing blocking artifacts
- True mathematically lossless compression available in the same format
- Extremely scalable: a single file can be decoded at various resolutions (thumbnails to full size) without loading the entire file
Limitations
- Very poor native web browser support prevents it from being a web standard
- High computational complexity makes encoding and decoding significantly slower than JPEG
- Early patent concerns and complex licensing hindered its initial adoption rate
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
JPEG-2000
Use JPEG-2000 when…
- Digital Cinema (DCP)
- Medical Imaging (DICOM)
- Geospatial Data
- Archival Preservation
WMF
Use WMF when…
- Legacy Microsoft Office Clip Art and Icons
- Windows GDI Graphics Export
- Early Windows Desktop Publishing