I think it is necessary to create a style guide line for the Cover Art Archive. Questions which seem important to me are:

• What type of picture (booklet containing lyrics, high resolution, etc.) is legally allowed (e.g. covered by fair use, etc.)
• For analog media: Is it allowed/preferable to upload a pure digital high-res picture of the front cover (more useful to display), or do we always prefer "real" photographs/scans (more useful for evidence)
• Is it allowed to upload pictures from external websites (discogs, avaxhome, label homepage), or only self-made scans/photographs?

The legality point is important in my opinion. With the cover art tab MusicBrainz is inviting people to upload images (to the Internet Archive), and the people who upload stuff can be easily traced back by copyright holders. So either MusicBrainz should write "You upload stuff at your own risk, please respect copyright!" (then every user can decide for himself, but is warned), or "you can upload these types (TODO) of cover art, it is governed by fair use".