Image MIME Reference
JPEG
JPEG Image
image/jpeg
VS
JPEG 2000 Part 2 (Extended)
image/jpx
JPX
A complete technical comparison of JPEG Image and JPEG 2000 Part 2 (Extended) — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.
JPEG wins on browser support
Feature Support
| Feature | JPEG | JPX |
|---|---|---|
| Transparency (Alpha) | ✕ No | Yes |
| Animation Support | ✕ No | Yes |
| Progressive Loading | Yes | Yes |
| HDR Support | ✕ No | Yes |
| EXIF Metadata | Yes | Yes |
| ICC Color Profile | Yes | Yes |
JPEG Image
image/jpeg
Extension
.jpg.jpeg.jpe.jfif
Container
JFIF / Exif
Compression
Lossy
Algorithm
DCT (Discrete Cosine Transform)
Color Depth
8-bit
Developed by
Joint Photographic Experts Group
Released
1992
Magic Bytes
FF D8 FF
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
Browser Support Comparison
| Browser | JPEG | JPX |
|---|---|---|
Chrome
|
✓ All
|
✕ |
Firefox
|
✓ All
|
✕ |
Safari
|
✓ All
|
✕ |
Edge
|
✓ All
|
✕ |
IE (Legacy)
|
✓
|
✕ |
JPEG
JPEG Strengths
- Universal support — every browser, OS, and application handles JPEG
- Excellent compression for complex photographs with natural color gradients
- Rich metadata support: EXIF (GPS, camera settings), ICC color profiles
Limitations
- No transparency — cannot have a transparent background
- Lossy compression introduces visible artifacts on sharp edges and text
- No animation support
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
JPEG
Use JPEG when…
- Photography
- Websites
- Social Media
JPX
Use JPX when…
- Prepress & Commercial Printing (CMYK)
- Geospatial Data
- Archival Preservation
- Medical Imaging