As I post this, the image we have for Cab Calloway is a small picture from TV Tropes, of him strutting on stage. Informative and representative, yes, but we don't know the license it's used under.
This file on Commons is larger, it shows him with a conductor's baton (thus showing what he did for a living), and it's definitely Public Domain. However, it isn't quite as kinetic a pose as what we have now.
On the whole, I think it's worthwhile replacing the TVT image with the Commons image. Am I correct?