Photos for iOS 8.4 is cropping/stretching my pictures to fit the iPad screen—how can I view them in the original aspect ratio?

I'm using Photos for iOS 8.4 on an iPad Air 2. I've uploaded some pictures in a 5:4 aspect ratio with pixel dimensions of 1921 x 1536. When I view them in Photos, the app resizes them to 2048 pixels wide and cuts off the top and bottom of the picture. How can I stop this behavior, and see my pictures at the correct size and aspect ratio, with no cropping?