Goof or some kind of inside joke?
At the very end (you'll have to freeze-frame to see it) notice when the detective carries the jester painting through the door, on the back of the canvas is the cartoon painting that Alice did the night of the murder.
I went back & watched the murder scene, and she definitely draws the cartoon on a different canvas on the other side of the room from the jester painting, so how/why did it end up on the jester's back?