Turn off window shade effect in Preview

When multiple JPG files are opened together in Preview, I can "flip" from one image to the next with the arrow keys or page up/down keys. But in Lion this "flip" is literally an animated window shade flipping effect. I find it distracting, and now it's actually intrusive because I want to quickly compare to very similar images by flipping back and forth repeatedly.

I cannot find a preference to turn off this "window shade" effect.

Any help?