This app was mentioned in 2 comments, with an average of 1.00 upvote
I've been looking for something like this so it seemed great - until I tried it. Manually tagging the corners, really? And then it still wasn't finding the right crop points for me for the ones I tried.
I gave up and went back through some apps I'd downloaded for the purpose before - most of them aren't much better but I did find Photomyne did basically what I was actually expecting it to - take a picture, and actually find and auto-crop it without all the extra fiddling. The process is still a lot slower than running multiple through a flatbed though
try photomyne. it's an easy to use app to scan your physical photos to digital Photomyne