BMP vs CUR Format Comparison
BMP
Bitmap Image File
image/bmp
VS
Windows Cursor
image/x-win-cursor
CUR
A complete technical comparison of Bitmap Image File and Windows Cursor — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.
BMP wins on browser support
Feature Support
| Feature | BMP | CUR |
|---|---|---|
| Transparency (Alpha) | ✕ No | Yes |
| Animation Support | ✕ No | ✕ No |
| Progressive Loading | ✕ No | ✕ No |
| HDR Support | ✕ No | ✕ No |
| EXIF Metadata | ✕ No | ✕ No |
| ICC Color Profile | Yes | ✕ No |
Bitmap Image File
image/bmp
Extension
.bmp.dib
Container
BMP / DIB
Compression
Uncompressed / RLE
Algorithm
NoneRLE (Run-Length Encoding)
Color Depth
1-bit, 4-bit, 8-bit, 16-bit, 24-bit, 32-bit
Developed by
Microsoft Corporation
Released
1985
Magic Bytes
42 4D
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 | BMP | CUR |
|---|---|---|
Chrome
|
✓ All
|
✓ 1
|
Firefox
|
✓ All
|
✓ 1
|
Safari
|
✓ All
|
✓ 1.2
|
Edge
|
✓ All
|
✓ 12
|
IE (Legacy)
|
✓
|
✓
|
BMP
BMP Strengths
- Universally supported across almost all operating systems, image editors, and programming languages
- Lossless quality (since it is typically uncompressed, no visual data is lost)
- Extremely simple file structure makes it easy to read and write programmatically
Limitations
- Massive file sizes make it entirely unsuitable for web delivery or network transfers
- No native animation support
- Lacks modern features like EXIF metadata and widespread transparency support
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
BMP
Use BMP when…
- Windows Desktop Wallpapers
- Legacy Windows Applications
- Simple Image Editing
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 BMP and CUR files.
Free Image Resizer
Editor
Resize, scale, crop, and modify dimensions for any photo or graphic.
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Image Metadata Remover
Privacy
Clean EXIF, camera, lens, and location tags from your photos.
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WebP to JPG Converter
Universal
Convert modern web images to universal high-compatibility JPG.
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Compress WebP Images
Optimizer
Reduce image file sizes for faster web performance.
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