Tap what's different!
Tap what's different!
If nothing is found for a while, one difference glows and the voice says "Look here!". Wrong taps never matter. With a keyboard, Tab into a picture, move with the arrow keys and press Enter. The voice is your device's own; nothing is sent anywhere, and nothing is saved.
Looking carefully and comparing: noticing that something is missing, a different colour, or bigger, and holding one picture in mind while looking at the other.