Hmm interesting. Going by the rules images I would say images of Clawdites at rest as it were. But it may be best to get an official answer from one of the Art team to see what they would accept.
I once asked the same question. The answer I was disappointed to receive is that you CANNOT just put a random race's picture on the Clawdite. The reason is that a Clawdite's shape shifting is a very specialized thing. Many Clawdite's can't even do it. For those who can they don't keep the shape forever, and it requires concentration and special oils to keep the skin from splitting. They can really only change color and hide their reptillian appearance. The especially gifted few can take the shape of most humanoids, but not races like Dugs or Ithorians.
Sorry. :( I once thought it would be the perfect chance to get some race pictures in for races the Combine didn't offer.
Not entirely true, Piico. Zam Wessel was actually indeed able to morph into a Dug during her and Jango's "mission" to Coruscant (forgot the name of the comic, but it was about a bomb or something).