XPose is a new touch-based interactive system for photo taking, designed to take advantage of the autonomous flying capability of a drone-mounted camera. It enables the user to interact with photos directly and focus on taking photos instead of piloting the drone. XPose introduces a two-stage eXplore-and-comPose approach to photo taking in static scenes. In the first stage, the user explores the photo space through predefined interaction modes: Orbit, Pano, and Zigzag. Under each mode, the camera visits many points of view (POVs) and takes exploratory photos through autonomous drone flying. In the second stage, the user restores a selected POV with the help of a gallery preview and uses direct manipulation gestures to refine the POV and compose a final photo. Our prototype implementation, based on a Parrot Bebop quadcopter, relies mainly on a single monocular camera and works reliably in a GPS-denied environment. A systematic user study indicates that XPose results in more successful user performances in photo-taking tasks than the touchscreen joystick interface widely used in commercial drones today.