Jake Archibald explains that Firefox is shipping JPEG XL support built on jxl-rs, the Rust decoder from Google Research that avoids the security surface of the 100,000-line C++ implementation. AVIF still wins on photos at lossy quality, but JPEG XL is better at lossless, at recompressing JPEGs, and at progressive rendering, so large images appear as they download. Test both with a representative set of your own images.
Intent to ship: JPEG XL
