Almost 5 years ago, we introduced Client side image optimization to enable users to upload pictures which were larger than the site limits, save user upload bandwidth, save community storage space, and make the user experience with images in Discourse snappier overall.
Building on top of that, there is a new Upcoming Changes that enables a few new features to this system:
GIF → Animated WEBP conversion
Converting large GIFs has been on our radar for a long time, and now they are converted to animated WebP, which averages half the size of the original file:
(2.5MB GIF → 1MB WEBP)
(10.1MB GIF → 4.8MB WEBP, wouldn’t be allowed by default in Discourse based on size)
HEIC conversion
We added support for HEIC in 2020 via server-side conversions, and we now also support handling those directly in the composer, giving the user visibility of the conversion result before a post is submitted. We kept server-side conversion working as a fallback if client-side fails for some reason.
(3.4MB HEIC → 650KB JPG)
JXL conversion
While the browser support for JXL files isn’t ready, users are now able to upload JXL files to Discourse and have those automatically converted to JPG so every user can see the image.
(1.1MB JXL → 930KB JPG)