1. An image processing apparatus comprising: a feature data calculating unit that calculates feature data of each image contained in a group of sequential images that are taken by an image taking apparatus; a distribution map generating unit that generates a distribution map that represents an overall trend of the group of sequential images; and a display control unit that displays the distribution map on a display unit, wherein the distribution map generator includes: a representative vector calculating unit that calculates a predetermined number of representative vectors that represent a plurality of images contained in the group of sequential images based on the feature data of the each image and a level of importance of the each image; and a representative vector arrangement determining unit that determines arrangement of the calculated representative vectors on the distribution map.