I was going to say, I scan screenshots of passes/codes all the time, including airplanes and busses. I haven't tried a photo, but I feel like there's a good shot it would work just fine. I wonder if a gallery app could be a poor man's pass app.
In China I was surprised a few years ago when my train ticket did not work like this. Needed data on to do a live update of the QR code, or something live in any case.
