Alternatively, might it be possible to put a "photo gallery" button on the "view photo" screen which would reopen the photo picker (similar in concept to how the "refresh" button on the clipboard let's you quickly look at new data)
My use case is that I'm going through Duolingo's Cantonese course, and constantly taking screenshots to look up new words. This would save a lot of clicks as I switch back and forth between the two apps to view the new images.