Maybe I’m the only one getting this (due to my old and increasingly cranky tablet), but I’m seeing preview pics not loading on older threads, like this one:
If I click on the filename, the image comes up, so the issue seems to involve the preview/in thread link, not the image itself:
It’s a minor thing, but it’s interesting. I’ve posted pics since the migration and they aren’t affected, but I’m not sure how relevant that might be since they’d be in my cache already, right? (But one of my old posts is also affected, so maybe not. 
)