How do you turn printed photos into digital photos? The laborious scanner method. Or, Google PhotoScan. Mark Hachman:
Google PhotoScan is an app both for Android and iOS, and works by using your phone’s camera to take several photos of a print photograph, using intelligence to stitch them together and mark the edges of the photograph. The photo stitching also works to eliminate glare from your phone’s flash, though a well-lit photo using natural light delivers the best results.
A scanner produces better results but these are not bad. I use a small tripod, good lighting, and then crank through as many printed photos as I can.