Is it not possible to use a special program to produce the images so that the participating member can then make few editing to them before publishing them to participate in the competition? I think this is somehow possible to happen.
Well, suppose that more than one participant uses the same program to produce an artwork, there is a small chance that the program will produce the same artwork for two members or more. I expect that this will be interpreted correctly so that there is no confusion and accusing the two participating accounts of being owned by one person and that this person cheats in the competition considering that it is not forbidden to have more than one account on the forum.