@sphx@gumbo To be fair we are responsible and do testing and backups and such on the regular, but that's not fun silly "birdbrain technology" characterization ya know. But also to be fair I did quite legitimately get blindsided by the PFP issues
image urls are normally passed to the ui in the data models they're displayed as part of (makes sense, designing it any other way would be insane)
for images in mfm though (@abc is technically mfm!), there isn't really any place to put data like that (mfm is just plain text, after all)! so we use the instance's name-to-object resolver urls
since resolving stuff is an expensive thing fedi software needs to do on the regular, misskey has a system of server-side caching set up. the cache life for emoji and avatars specifically is 24 hours, so inconsistencies can still happen but clear up in a day