WebP is an image format Google introduced in 2010 that compresses images to noticeably smaller file sizes than JPEG or PNG at comparable visual quality, using more efficient compression techniques than those older, decades-old formats were built with.
It supports both lossy compression (similar to JPEG, trading some quality for a smaller file) and lossless compression (similar to PNG, no quality loss, still smaller), plus transparency and animation in a single format, which is genuinely more flexible than needing separate JPEG, PNG, and GIF files for different needs. Browser support is now effectively universal across modern browsers, which removed what used to be the main practical argument against adopting it broadly. Converting a site's images to WebP (with a fallback for any rare unsupported context) is one of the more reliable, relatively low-effort wins for page speed available, especially on image-heavy pages where the format switch alone can meaningfully cut total page weight without touching anything else about how the page is built.
