CUR vs JXL Format Comparison
CUR
Windows Cursor
image/x-win-cursor
VS
JPEG XL
image/jxl
JXL
A complete technical comparison of Windows Cursor and JPEG XL — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.
CUR wins on browser support
Feature Support
| Feature | CUR | JXL |
|---|---|---|
| Transparency (Alpha) | Yes | Yes |
| Animation Support | ✕ No | Yes |
| Progressive Loading | ✕ No | Yes |
| HDR Support | ✕ No | Yes |
| EXIF Metadata | ✕ No | Yes |
| ICC Color Profile | ✕ No | Yes |
Windows Cursor
image/x-win-cursor
Extension
.cur
Container
ICO/CUR Container File
Compression
Uncompressed (BMP) / PNG (Supported in newer versions)
Algorithm
None (DIB / BMP)Deflate (If PNG embedded)
Color Depth
1-bit (Monochrome), 4-bit (16 colors), 8-bit (256 colors), 24-bit (True Color), 32-bit (True Color with Alpha)
Developed by
Microsoft Corporation
Released
1985
Magic Bytes
00 00 02 00
JPEG XL
image/jxl
Extension
.jxl
Container
ISOBMFF / JPEG XL Codestream
Compression
Lossy (VarDCT) / Lossless (Modular)
Algorithm
VarDCT (Variable block-size DCT)Modular (Predictive coding for lossless)
Color Depth
8-bit, 10-bit, 12-bit, 16-bit, 32-bit (Float)
Developed by
Joint Photographic Experts Group (JPEG)
Released
2021
Magic Bytes
FF 0A (Codestream) / 00 00 00 0C 4A 58 4C 20 0D 0A 87 0A (Container)
Browser Support Comparison
| Browser | CUR | JXL |
|---|---|---|
Chrome
|
✓ 1
|
✕ |
Firefox
|
✓ 1
|
✕ |
Safari
|
✓ 1.2
|
✓ 17+
|
Edge
|
✓ 12
|
✕ |
IE (Legacy)
|
✓
|
✕ |
CUR
CUR Strengths
- Natively supported by Windows for desktop cursor customization
- Widely supported by modern web browsers for custom CSS cursors
- Supports an exact hotspot coordinate, which standard image formats like PNG and JPEG lack
Limitations
- Legacy format that is being gradually replaced by SVG and PNG for web implementations
- Does not support animation (animated cursors use the distinct .ani format)
- The MIME type is highly fragmented across systems (e.g., image/cursor, image/x-win-cursor, application/x-cursor)
JXL
JXL Strengths
- Capable of losslessly recompressing legacy JPEG files, saving ~20% space while retaining perfect byte-for-byte restorability
- Highly superior progressive decoding (Saliency-driven), allowing recognizable images to load extremely fast on slow connections
- Outperforms WebP and competes favorably with AVIF, especially at high-fidelity settings and for complex textures/photography
- Royalty-free with an open-source reference implementation (libjxl)
Limitations
- Google's removal of JXL support from Chrome severely hindered its adoption as a universal web standard
- Lack of hardware decoding chips compared to video-derived codecs like AVIF (AV1)
- File parsing logic is complex due to the split between raw codestreams and ISOBMFF containers
When to choose which format
CUR
Use CUR when…
- Operating System Custom Cursors
- Custom Web Browser Mouse Pointers (via CSS)
- Desktop Application UI
JXL
Use JXL when…
- High-End Web Delivery (via Safari/Polyfills)
- HDR Photography
- Legacy JPEG Archiving
- Digital Art & Image Storage
Convert & Edit Online
Free online web tools for CUR and JXL files.
Free Image Resizer
Editor
Resize, scale, crop, and modify dimensions for any photo or graphic.
Use Tool
Image Metadata Remover
Privacy
Clean EXIF, camera, lens, and location tags from your photos.
Use Tool
WebP to JPG Converter
Universal
Convert modern web images to universal high-compatibility JPG.
Use Tool
Compress WebP Images
Optimizer
Reduce image file sizes for faster web performance.
Use Tool