Facebook Rolling Out New iOS Photo Sync Feature
Facebook is slowly rolling out a new Photo Sync feature to its iOS users that automatically uploads all photos taken on the iPhone to a private photo album on Facebook. The idea is to make it easier and faster for users to share photos with their friends.
Facebook's support site has much more about Photo Sync, as well. Facebook is using background uploads within the Facebook iOS app to move the photos, not anything special with location APIs or Apple's iOS 6 Facebook integration.
The app is very clear that all photos uploaded automatically are marked as private and cannot be viewed by others until specifically shared by the user. Users get 2 GB of complimentary photo storage.
MacRumors.com