On a slightly related note, I think I'll reject a portrait submission without the source, because the first thing we have to affirm is if the portrait is real and thus we need the URL or such. There were at least two cases where a modestly-known composer was associated with the wrong photo (
one of the composers posted even a blog entry about it, though it seemed to be Last.fm's fault). To be fair, many of my older submission lack the credits, so I must work on replacing them from now on.