There are already so many good ideas here, but here's another one. Is your friend an OZ fan of just the movie, or the books as well? In the books, the land is divided up into four quadrants, with the Emerald City being in the middle. The Muchkins are blue, the Winkies are yellow, the Quadlings are purple, and the Gillikans (sp?)are red (sorry, can't spell them). You could use bright or muted colors of these to frame each picture. Of course, if she only loves the movie, the four colors won't mean much to her. Just one more idea.