1. An image processing apparatus comprising: an input port for receiving a projection image of a device acquired whilst said device resides at a position relative to an object, the object capable of transitioning between at least a first and a second object state and said device repositionable; an object state determiner configured to determine a current state of the object; a device localizer configured to use image information in the received projection image to determine the position of the device; an object image selector configured to select from of a plurality of stored object images grouped according to the first object state and the second object state, wherein at least one group comprises more than one of the object images, a contextual object image i) whose group corresponds to the determined object state and ii) whose image information is indicative of the determined device position; and a graphics display generator configured to generate for display on a screen a combined image including a part of the selected contextual object image and the received device projection image.