1. An image processing apparatus comprising: image storing means that stores a plurality of content blocks of images, wherein each image has associated time information, and two of the content blocks of images were taken by different imaging devices and contain an overlap portion set of images that have overlap within a section of shooting time; feature extracting means that extracts feature amounts of each image stored in the image storing means; image selecting means that selects at least one of images included in the overlap portion set, stored in the image storing means, on the basis of the feature amounts associated with the respective images included in the overlap portion set; and digest-image generating means that generates a digest image of the images stored in the image storing means on the basis of the selected images, wherein the digest image includes at least one selected image from each of the two content blocks of images such that the selected images do not overlap within the section of shooting time.