Does this photograph look familiar to you?
Norman Rockwell had the photograph taken to use as a reference for his famous illustration, After the Prom. You can see more of his photos at this great article I found on Photo District News. NPR also has an article comparing Rockwell's photos and paintings.
Because I've always drawn portraits from photographs, I used to worry that maybe I was "cheating" somehow, and that a "real" artist would be able to draw portraits without the help of a photo. In art school I have been relieved to discover that illustrators often use photographic references for their drawings - very few, except maybe comic book artists, work purely from imagination.
(Look how he exaggerated the policeman's shoulders!)
I've always admired Norman Rockwell, and it's good to see that his artwork came from both photographs and his imagination.