Preview quality

Pillow vs ImageMagick vs libvips on the 2000 px client previews (JPEG q88)

Pipeline	Time	RAM	Size	Score

Time and RAM: whole process on one core like the prod container, best of 3. Python rows include about 95 ms of interpreter startup the prod server never pays.

Score: SSIMULACRA2 against lossless float downscales of the original (mean of 3 references), higher is better, 100 is identical. The lossless reference shown here is ImageMagick HDRI Lanczos with no JPEG step.