Chrome shipped JPEG XL on October 6. Image codec support on the web has been a decade-long queue, and the JPEG XL entry finally cleared: the announcement frames it as better compression than JPEG, built-in HDR support, and lossless transcoding of existing JPEG files.

Why transcode-and-preserve matters

Lossless JPEG transcoding means an existing .jpg can be recompressed into .jxl byte-per-byte preserving pixels, then decoded back exactly. Archives, photography portfolios, and anyone with twenty years of JPEGs can re-encode without regenerating from raw files. For new uploads, the pitch is simple: smaller files at the same quality.

The static-site playbook

  1. Keep shipping webp today; it is universally supported and free. No rush, no rewrite.
  2. Ban a format decision on browser support alone until the whole matrix is real: use the picture element with a jxl source ahead of webp, and browsers that lack it simply skip the line.
  3. Measure: this site keeps every hero under 60 KB at its -800 breakpoint because image bytes drove its LCP, a defect we measured then fixed. A new codec only helps ports that keep their budgets.
Formats do not ship pixels; the smallest file that survives an old phone on cheap LTE does. That is the only gacor metric in town.