OK so one of the numerous Star Wars forums had a picture posted that's clearly a frame from "Revenge of The Sith". It is Yoda, in a room.
See this scene in the film here.
Check out the concept art for the scene here.
Only view if you're not too bothered about the potential for it to spoil one or more moments of the film. You have been warned. By the way, the pic of the concept art looks like its from one of the posts from behind the scenes or the recent DVDs.