Apple-ICNS vs CUR Format Comparison
Apple-ICNS
Apple Icon Image
image/x-icns
VS
Windows Cursor
image/x-win-cursor
CUR
A complete technical comparison of Apple Icon Image and Windows Cursor — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.
CUR wins on browser support
Feature Support
| Feature | Apple-ICNS | CUR |
|---|---|---|
| Transparency (Alpha) | Yes | Yes |
| Animation Support | ✕ No | ✕ No |
| Progressive Loading | ✕ No | ✕ No |
| HDR Support | ✕ No | ✕ No |
| EXIF Metadata | ✕ No | ✕ No |
| ICC Color Profile | Yes | ✕ No |
Apple Icon Image
image/x-icns
Extension
.icns
Container
Chunk-based (OSType Header)
Compression
Uncompressed (Legacy) / PNG (Modern) / JPEG 2000 (Modern)
Algorithm
NoneDeflate (via embedded PNG)Wavelet (via embedded JP2)
Color Depth
1-bit (Monochrome), 4-bit, 8-bit, 24-bit (RGB), 32-bit (RGBA)
Developed by
Apple Inc.
Released
2001
Magic Bytes
69 63 6E 73
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
Browser Support Comparison
| Browser | Apple-ICNS | CUR |
|---|---|---|
Chrome
|
✕ |
✓ 1
|
Firefox
|
✕ |
✓ 1
|
Safari
|
✕ |
✓ 1.2
|
Edge
|
✕ |
✓ 12
|
IE (Legacy)
|
✕ |
✓
|
Apple-ICNS
Apple-ICNS Strengths
- Seamlessly handles multi-resolution scaling on macOS, perfectly serving both standard and high-DPI (Retina) displays from a single asset
- Modern versions efficiently embed standard PNG files, making it much easier to parse the high-resolution layers than the legacy raw pixel formats
Limitations
- Strictly bound to the Apple ecosystem; completely useless natively on Windows, Linux, or the Web
- The internal chunking structure is notoriously messy, utilizing dozens of different undocumented, legacy OSType tags spanning 20+ years of Apple history
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)
When to choose which format
Apple-ICNS
Use Apple-ICNS when…
- macOS Application Bundles (.app)
- macOS Folder Customization
- Apple Disk Image (.dmg) Styling
CUR
Use CUR when…
- Operating System Custom Cursors
- Custom Web Browser Mouse Pointers (via CSS)
- Desktop Application UI
Convert & Edit Online
Free online web tools for Apple-ICNS and CUR files.
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