>>108205526
It's not pretty but half the time the damage is "acceptable" as long as the original JPG was saved with high quality settings and uses 4:2:0 chroma sub sampling. Phone cameras for example due to hardware acceleration constraints save JPGs in 4:2:0 so Webp is okay here. Someone saving a screenshot of vidya and manually saving it to 4:4:4 via cjpegli is better left un-tarnished by Webp.
When I ffprobed a modern Android 16 camera image I get this: Stream #0:0: Video: mjpeg (Baseline), yuvj420p(pc, bt470bg/unknown/unknown), 4080x3060, 25 fps, 25 tbr, 25 tbn
If anyone is curious about the technical stuff, 4:2:0 uses 50% less RAM than 4:4:4. While using 4:2:0 makes you shit and piss your pants there is a usecase for it.