While I don’t think this is the best idea for magic app, if someone made it, I would buy it. The premise is someone names a place and time and that’s the meta data on the photo. The app would change the meta date for a picture. Ideally this would be a picture that you text someone, but could be on your phone.
I’m going to imagine that it wouldn’t be hard for someone to make an app that does that. You could key in the state and time info when you use your six digit unlock screen.
I don’t think the trick is strong enough for a stand alone trick, but used in conjunction with something else as a kicker to a prediction. Like maybe it’s a confabulation, so the picture is one reveal, and the date and time are another reveal.
-Louie