Thread:RaiderZ/@comment-9758981-20191108000007/@comment-24751497-20191108001454

We indeed have an image policy in place as a section on the general policy page. See the link below for reference.
 * Project:Policy

As for file type regulation you suggested: pngs and gifs are indeed higher in quality than jpegs, but when the files have a very large file size (4-5 MB or more) or image size, they take a lot longer to load for viewers looking at them for the first time.