Given that the first and last frames are identical copies of each other (and therefore obviously ot drawn twice) I think it's a dead cert that the picture was removed intentionally.
To a techie, an "art" is a "technique" (or "invention" in some cases).
I just took your observation that Scott might have intentionally omitted the portrait from the last frame, to be implying a technique of his, and punned on the term "art".