Retro, a photo-sharing app for friends, lets you ‘time-travel’ through your camera roll

Retro, a friend-focused photo-sharing app with roughly a million users, is adding a new feature that lets you time-travel through your old photo memories from your phone’s camera roll. While the app today offers a way to share photos of what’s happening during your week with a private group of friends, or create shared albums, this latest addition, dubbed “Rewind,” is private to you — unless you choose to share the photos with others.

Retro’s co-founder, Nathan Sharp, explains that the idea for Rewind was inspired by a feature the app…