@pixelfed storage isn't free or unlimited. how do you fund the platform in a independent and sustainable way so it does not have to close in 3 months?
flickr had a limit of 1TB for free accounts (now it's 1000 images). are you really okay with people upload 2 or 5TB? maybe a payed account would be better long term (with first TB free)?
are you able to make sure the images will be available in 20 years, like flickr did?