Scroll through Local here and you will see. Communities and users that are local to this Lemmy.one have a black box for a photo. Viewing the profile/community from another instance displays the black box as well. It seems that users who have not set a custom profile picture just have a default Lemmy lemur icon, and that displays just fine.

If I try to upload a new profile photo, I get the following error:

Request error: error sending request for url (http://pictrs:8080/image): error trying to connect: tcp connect error: Connection refused (os error 111)