Mozilla to enable default JPEG XL support in Firefox 157

Mozilla has announced that Firefox 157 will enable default support for the JPEG XL (JXL) image format across all platforms. This update, expected by late September, marks a significant shift for the browser, moving the format from experimental Nightly builds to a standard feature without requiring manual configuration.

The decision was driven by security concerns regarding previous C++ implementations. Mozilla required a memory-safe decoder, leading to the adoption of 'jxl-rs', a Rust-based decoder developed by Google Research. This implementation provides full support for progressive rendering, allowing images to load incrementally to improve perceived web speeds.

While JPEG XL offers advantages in lossless compression and backward compatibility with existing JPEG files, Mozilla suggests it will coexist with AVIF. JPEG XL is recommended for high-quality photo compression and progressive loading, whereas AVIF remains highly efficient for general lossy compression of UI elements and standard web imagery. Major browsers are expected to widely support the format by 2026.