If you rely on Facebook's "hide from my timeline" option to bury your unflattering photos, we have some bad news.
Before you rush to delete your account altogether, we're here to tell you that it's not as bad as it sounds. The app can't actually change someone's privacy settings. So, if you've hidden your photos from the public altogether, they'll remain hidden. What Picturebook does is make photos that are hidden from timelines easier to find.
If you want to stop your embarrassing or private photos from being dug up on Picturebook, either untag yourself from your hidden photos, or make sure that none of your images are marked as "public."