ICO
Windows Icon
ICO is the format Windows uses for application and file-type icons. A single .ico file is a container that can hold multiple versions of the same image at different resolutions and color depths (e.g., 16×16 at 8-bit and 256×256 at 32-bit with alpha), allowing Windows to pick the most appropriate version for each display context. ICO files are also used as favicons — the small icon displayed in browser tabs — although modern browsers additionally accept PNG and SVG for this purpose.
| File extensions | .ico |
| MIME type | image/x-icon |
| Developer | Microsoft |
| First released | 1985 |
| Category | Images |
| Open standard | No (proprietary) |
What opens ICO files
- Microsoft Windows (natively, as application/system icons)
- Adobe Photoshop (with plugin)
- GIMP
- IcoFX
Browse File Formats
Reference details for 53 file formats — extensions, MIME types, what opens each one, and how they convert.
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