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.