I doubt he's making the actual paintings - if they're really new paintings and not simply Photo Shop as claimed.
I really think if the artist is unknown, s/he would have a problem with someone else, who claims to not even know who s/he is, taking his/her original creations and printing back variations, gold, silver, diamond, uncut sheets, vertical doubles, horizontal doubles, quads, and creating printing plates to sell without paying some sort of royalties. Even Topps isn't that bad.