Is there a maximum size for Kbin thumbnails to federate from other instances?

Posting pictures from Lemmy.world since I still have trouble uploading on Kbin, but sometimes the pictures don't appear as a thumbnail on Kbin regardless of how long I wait for it to federate. Clicking on it still opens the direct image link, but there's no thumbnail when scrolling past in the feed. Is there a max image size or something I'm hitting for federation?