Only... whatever you want !
Openclipart is just about freedom. For example, it is not a safe, where public domain material is kept under lock and key, neither the public domain all by itself. I prefer to think OCAL as a place where authors can freely share their works so that they can be diffused and reused without limit, no more, no less. Not a place of renunciation, where authors can no longer claim paternity over their creations, however humble they may be. Only Wine's work was inspiring, that's the only thing I'll remember - thanks for this.