Facebook is testing out a new way to detect your friends faces in your camera roll when you take pictures. They are calling this Photo Magic. Facebook will send you a push notification within a few minutes suggesting that you send the photo to those friends via Messenger. Photo Magic uses the same technology that is used for tag suggestions when posting a photo on Facebook.
Facebook thinks that users get a little creeped out by this kind of technology. You can opt in or out of having your face detected. This technology is being tested in Australia for now, but the goal is to bring it to more countries.
I think this is a really cool idea. It gives people more of an incentive to post their photos on Facebook or share them with friends since the push notification is already there suggesting that you do. I would definitely use this technology if it comes to the US. Facebook never fails on coming up with new ways to keep their users on their toes.