The seem like a really great especially because it allows for a photo graphic overlay of the prior photo, allowing you to lineup each image. However, the app lost my profile not once but twice. I had selected the iCloud photo back up which means that my photos were saved. But losing a Profile means that each time your profile is lost you have to re-upload your weekly photos and real align and crop them accordingly. I did this once but twice is ridiculous. Use another app! (note I was using an iPhone 6 S+)
Jkb151 about Changes - Face Tracker, v2.3