ICO (Windows icon format)
ICO is the Windows icon format, also used for website favicons. Learn which sizes an ICO file should contain and how to create one from PNG or JPG.
- Type
- Image
- File extensions
- .ico
- MIME type
- image/vnd.microsoft.icon
What is ICO?
An ICO file is a container that holds one or more images of different sizes, such as 16×16, 32×32 and 48×48 pixels. Windows and browsers pick the size that fits best.
Websites traditionally serve favicon.ico from the site root. Modern browsers also accept PNG and SVG favicons, but ICO remains the most compatible choice.
When to use ICO
- Website favicons
- Windows application and shortcut icons
Limitations
- Each embedded image is limited to 256×256 pixels
- Not meant for general images
Compatibility
Supported by all browsers as a favicon and by Windows as an icon format.