The paint point here was very large uploaded PNGs which had absolutely no business being lossless PNGs, when they could be lossy JPGs at 1/5 or less the size. For small images (1280x720 or less) it does not matter so much, but get to 1080p++ and the cost becomes .. extreme.
1,651,936 Screenshot_2017-04-16-21-23-50.png
1,701,243 Screenshot_2017-04-16-21-23-54.png
323,789 Screenshot_2017-04-16-21-23-50.jpg
288,995 Screenshot_2017-04-16-21-23-54.jpg
This also has super bad ramifications for PNG optimizers which take n2 or worse time as the image gets larger.. here’s pngout.exe behavior by image size:
960x540
s1 → 2.1s
s2 → 2.2s
1280x720 (720p)
s1 → 3.7s
s2 → 3.2s
1920x1080 (1080p)
s1 → 32s
s2 → 33s
3840x2160 (4k)
s1 → 57s
s2 → 42s