With all due respect, you must ask yourself: why would the U.S. Navy Blue Angels fly F-18s in air shows and practice in WWII era prop planes? The answer is simple... they don't. The Angels practice and perform in the same planes. The picture you posted is, more than likely, a picture of the Skytypers demonstration team. The company is know for their skywriting but also has a flight demonstration team that practices quite often and travels the air show circuit.
A closer look...
My best guess, but that certainly was not the Blue Angels.