I was amazed at how much better compression webp offered over jpg and png.

Using it in a web-browser 360 panorama viewer enabled pretty substantial latency and storage improvements.

close to 4x iirc.

ditto large "xray" style orthographic images of building scans generated from pointcloud laser scan data.

avif was even better compression for some cases, but seems to take a long time to generate, and less widespread browser support. Will look at jpeg-XL .. but Im guessing it will be a while until it has widespread support