current situation is result of StreetComplete maintainer will to temporarily host photos, but not deal with all headaches of hosting permanent collection.

Note that dedicated StreetComplete image server exists after lut.im used to store images was shut down due to abuse of this service and framapic that replaced it was shut down due to abuse and one of recommended framapic replacement (https://wtf.roflcopter.fr/maintenance.html ) is also already shut down for the same reason. We want to avoid dealing with any such issues.

See also

    https://wiki.openstreetmap.org/wiki/Category:Media_without_a_proper_attribution
    https://wiki.openstreetmap.org/wiki/Category:Media_without_a_license
    https://wiki.openstreetmap.org/w/index.php?title=Special:UncategorizedFiles&limit=500&offset=7000

Just OSM Wiki has thousands of images waiting for content review/replacement/deletion. With things improving very slowly (at current rate it will take at least decades to process just already known problems). 