Hello,
You can read this in the rule :
The task is simple: Create fun fan-art based on the Gibberlings from Prostostore, using any graphic tool you prefer!
I'm not sure about the difference between "drawing" or "design", but i hope that "any graphic tool" can answer your question ?
In our FR explanation, they say "an illustration" (not a photomontage or cartoon for exemple). So a drawing (manually/scanned or directly on a computer) seems to be what is expected ?