To print a single photo to an AirPrint enabled printer, tap , then tap Print. To print multiple photos while viewing a photo album, tap Select, and tap to select the photos you want to print. Tap , then tap Print. More: AirPrint Basics
To share to Twitter, Facebook, Flickr, or Vimeo directly from the Photos app, sign in to your account in Settings. Then, just tap in Photos or any other app that supports sharing photos and videos.