It might be good to introduce a new "Packaging" cover art type for scans which include the packaging, similar to how the "Watermark" one works. Ie., it shouldn't be for just uploading images of empty jewel boxes, but if one does a front scan of a jewel box release without taking the booklet out, it should be marked both "Front" and "Packaging".

Some examples:
https://musicbrainz.org/release/6711d291-12ed-4cbc-b4ea-b37bcd4c60eb/cover-art
https://musicbrainz.org/release/b8ef1feb-131d-4d35-ae7d-f75f4e31db87/cover-art