Thanks for asking my opinion.
Here is what I'd say about the Catahoula pic that you mentioned: 1) If the image is of a mixed breed dog, then it should be replaced. 2) However, many Catahoula's are of a mixed breed, since a breed standard doesn't seem to exist. I believe the UKC recognizes them as a distinct breed, but their rules are less strict because of their emphasis on dog performance, rather than conformation. One can point to a dog and say, "this is a Catahoula", and there really is no way to argue that it is not unless the dog is blatantly non-Catahoula-esque. Having said that, don't misconstrue my comment as elitist. I'm not big on conformation, and believe too much ado is made regarding breed standards. In fact, I believe that breeding to a particular standard is doing harm to many breeds. 3) I would encourage you to find a good copyright-free image of a Catahoula and replace the current pic, if it is important to you. If you believe you lack the technical expertise to do the editing, I'd be happy to do it for you.
Personally, the image looks like a Catahoula to me. In my experience, they vary greatly in color, size, and shape. I've seen Catahoulas the size of Brittanies, and Catahoulas the size of Great Danes. This is probably because anyone can breed Catahoula-like pups, and sell them to an unsuspecting public. If you didn't know the truth about the image, would you still argue that the dog depicted was not a Catahoula?
Cordially,
Will