How do ICO and AVIFcompare? Here's everything you need to know to choose the right format — and how to convert between them.
Icon File Format
ICO is the icon file format used by Windows for application icons and website favicons. It can contain multiple image sizes and color depths in a single file.
AV1 Image File Format
AVIF is a next-generation image format based on the AV1 video codec. It offers the best compression ratios available today — significantly better than WebP and JPG — while being royalty-free and open source.
| Specification | ICO | AVIF |
|---|---|---|
| Full name | Icon File Format | AV1 Image File Format |
| Extension | .ico | .avif |
| MIME type | image/x-icon | image/avif |
| Category | Image | Image |
| Developer | Microsoft | Alliance for Open Media |
| Year introduced | 1985 | 2019 |
| Compression | Lossless | Lossy |
Both ICO and AVIF have their strengths. ICO excels at website favicons, while AVIF is better for cutting-edge web performance optimization.
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