Convert ICO to WebP

The ICO format is an image container specifically designed for Microsoft Windows to store icons for executable files, folders, and applications. Introduced with Windows 1.0, it can encapsulate multiple raster images of varying dimensions and color depths (specifically BMP or PNG frames) within a single file to support dynamic scaling across different display resolutions. The structure comprises an ICONDIR header referencing one or more ICONDIRENTRY directory entries, allowing the operating system to select the appropriate 16x16, 32x32, or 48x48 pixel resource based on the current UI scaling settings.

ICO files are natively supported by the Microsoft Windows operating system, which automatically renders them in the File Explorer and taskbar. On macOS, Apple Preview handles the format natively. For editing or detailed inspection of the contained bitmap layers, raster graphics editors such as GIMP, Adobe Photoshop (via plugin), or Paint.NET are required. Web browsers also natively render ICO files when they are designated as favicons.

WebP is a raster graphics file format developed by Google specifically for web optimization, utilizing the Resource Interchange File Format (RIFF) container. It employs predictive coding based on the VP8 video codec for lossy compression and the LZ77 algorithm with entropy coding for lossless compression. WebP supports transparency (alpha channel) in both lossy and lossless modes, as well as animation, often achieving file sizes 26-34% smaller than comparable JPEG or PNG files while maintaining high structural similarity (SSIM) index scores.

WebP is natively supported by all modern web browsers, including Google Chrome, Mozilla Firefox, Microsoft Edge, and Apple Safari. For offline viewing, Windows 10 and 11 support WebP via the Photos app (often requiring the Webp Image Extensions package), while macOS users can view them in Preview (macOS Big Sur and later). Legacy systems or incompatible editors require conversion tools or third-party viewers like IrfanView to render the image data.