Photo layout issue on modern phones

In our Subjective iPhone app (please go buy it and rate it-- the "instant" filters have hit a sweet spot IMO) we've had many discussions on a layout issue I will share here.

Almost all mobile cameras now produce 4x3 images (since the optical system has a round lens, I do wonder why it is not 1x1.   Any ideas?), and almost all mobile screens are now 16x9, how do you display the images on a phone?   Here are the "natural" ways to put 1, 2, 3, 4, 6  4x3 images on the  16x9 screen (5 there is no "pretty" way).   After 6, things get too small IMO.

1,2,3,4,6 4x3 rectangles on a 16x9 screen

In our app, we wanted to do the "pick your favorite" UI inspired by A/B testing, subjective refraction at the optometrist, and Photoshop variations.   So 1 is great but doesn't cut it.   6 in a circle like Photoshop uses in the natural choice for big screens and 2D color spaces, but our screen is small and we often are not just navigating a 2D space.   If we want the long axis of the rectangles to match up (so you'll be holding the phone in portrait orientation for editing a portrait mode pictures, then 4 and 6 are really the only options.   We found 6 to be both too many choices, and too small pictures.   And like most engineers, we like it when there is exactly one good design choice :)