Some of Degas' paintings with the photos he painted them from.

I remember thinking it was kind of interesting that I saw in a video and then read in a couple of books how much Dégas use photographic reference material. In fact, something that I don't like to admit that I do, which is I use projected images to establish the drawing, it turns out that Dégas did that all the time. Dégas would actually take the negatives and put them in a "lantern style projector" them onto the canvas and sketch it out.