> it doesn't help reddit's case that much. After looking into what it's actually downloading in my "desktop" test, there are lots of huge PNG images (1000x1000 +) that seem to be displayed as tiny thumbnails.
I'm not able to reproduce this either. Here's a desktop WPT run: https://www.webpagetest.org/result/210707_BiDcXB_65148b09266...
Could you share a screenshot, or a link to one of these oversized PNGs?