50 C.F.R. § 91.14
A live portrayal of any bird(s) of the five or fewer identified eligible waterfowl species must be the dominant feature of the design. The design may depict more than one of the eligible species. The judges' overall mandate is to select the best design that will make an interesting, useful, and attractive duck stamp that will be accepted and prized by hunters, stamp collectors, conservationists, and others. The design must be the contestant's original hand-drawn creation. The entry design may not be copied or duplicated from previously published art, including photographs, or from images in any format published on the internet. Photographs, computer-generated art, or art produced from a computer printer or other computer/mechanical output device (airbrush method excepted) are not eligible to be entered into the contest and will be disqualified. An entry submitted in a prior contest that was not selected for a Federal or State stamp design may be submitted in the current contest if the entry meets the criteria set forth in this section.
50 C.F.R. §91.14