This is an archived snapshot of W3C's public bugzilla bug tracker, decommissioned in April 2019. Please see the home page for more details.
The table at 4.8.11.2 (Serializing bitmaps to a file) says that for image/jpeg format, the second argument of toDataURL() “must be treated as the desired quality level”. There is no definition for what “quality level” means here and what effect it has, and the old JPEG specification cited, http://www.w3.org/Graphics/JPEG/jfif3.pdf does not define it either (it does not contain the word “quality”).
HTML5.1 Bugzilla Bug Triage: Won't fix, quality/compression is actually defined in the specification for JPEG. https://www.iso.org/obp/ui/#iso:std:iso-iec:10918:-1:ed-1:v1:en If this resolution is not satisfactory, please copy the relevant bug details/proposal into a new issue at the W3C HTML5 Issue tracker: https://github.com/w3c/html/issues/new where it will be re-triaged. Thanks!