Here's a nice, hi res pic of the TMNT IV: Turtles in Time video game box art:
Well, it's the European version, "Hero Turtles", but close enough.
For the life of me, I do not know who is responsible for that particular piece. I really like it, though; it has that look of Mirage about it and I doubt it was one of Konami's in-house Japanese artists. If you know who to credit, give me a heads up.