Image MIME Reference
JPEG-XR
JPEG XR (HD Photo)
image/vnd.ms-photo
VS
PTI Image (Personal/Vanity Tree)
image/prs.pti
PTI
A complete technical comparison of JPEG XR (HD Photo) and PTI Image (Personal/Vanity Tree) — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.
Equal browser support
Feature Support
| Feature | JPEG-XR | PTI |
|---|---|---|
| Transparency (Alpha) | Yes | ✕ No |
| Animation Support | ✕ No | ✕ No |
| Progressive Loading | Yes | ✕ No |
| HDR Support | Yes | ✕ No |
| EXIF Metadata | Yes | ✕ No |
| ICC Color Profile | Yes | ✕ No |
JPEG XR (HD Photo)
image/vnd.ms-photo
Extension
.jxr.wdp.hdp
Container
TIFF-like Image File Directory (IFD)
Compression
Lossy (Lapped Bi-orthogonal Transform) / Lossless
Algorithm
Lapped Bi-orthogonal Transform (LBT)
Color Depth
8-bit (Grayscale, RGB, CMYK), 16-bit, 32-bit Floating Point (HDR)
Developed by
Microsoft Corporation (later Joint Photographic Experts Group)
Released
2006
Magic Bytes
49 49 BC 01
PTI Image (Personal/Vanity Tree)
image/prs.pti
Extension
.pti
Container
Proprietary
Compression
Unknown / Proprietary
Algorithm
Unknown
Color Depth
Unknown
Developed by
Jürn Laun
Released
1999
Magic Bytes
Unknown
Browser Support Comparison
| Browser | JPEG-XR | PTI |
|---|---|---|
Chrome
|
✕ | ✕ |
Firefox
|
✕ | ✕ |
Safari
|
✕ | ✕ |
Edge
|
✕ | ✕ |
IE (Legacy)
|
✓
|
✕ |
JPEG-XR
JPEG-XR Strengths
- Excellent support for 16-bit and 32-bit floating-point HDR images without massive file size bloat
- Native support for alpha transparency, which standard JPEG fundamentally lacks
- Computational complexity for decoding/encoding is relatively low, making it hardware-friendly
Limitations
- Suffered a complete failure of adoption in the web browser market outside of Microsoft's ecosystem
- Fully superseded by modern, open formats like WebP, AVIF, and JPEG XL which offer better compression and universal browser support
- Multiple file extensions (.wdp, .hdp, .jxr) and MIME types cause confusion and parsing fragmentation
PTI
PTI Strengths
- Provided a registered MIME type namespace for a specific application's proprietary image format without conflicting with standard web types
Limitations
- Completely undocumented and unsupported in modern ecosystems
- Zero web browser compatibility
- Falls into the 'vanity' tree, making it irrelevant for standard cross-platform data exchange
When to choose which format
JPEG-XR
Use JPEG-XR when…
- Legacy Windows Desktop Backgrounds
- XPS (XML Paper Specification) Documents
- Early High Dynamic Range (HDR) Photography
- DirectX Textures
PTI
Use PTI when…
- Legacy Application Specific Workflows
- Proprietary Image Storage