Photomancy is activated with the hotkey 'Z' which is fairly close to 'X', the button used to interact with almost everything in the game.
Whether you click on it accidentally or on purpose, the only way to exit Photomancy (that I'm aware of) without taking a photo is clicking the red 'x' button. I've found it easier (and faster) to just hit 'Z' to take the photo and the game will immediately exit Photomancy with a photo taken.
Seeing as the escape key 'Esc' can be used to exit most screens in the game (crown shop, backpack, etc), it would be fantastic to have it exit Photomancy too (really I'd take any key).
