1. A image processing apparatus that processes an image of inside of a subject, the image acquired by a capsule endoscope that is introduced into the subject and captures images of the inside of the subject, the image processing apparatus comprising: an image extraction unit that extracts, from a first image group acquired by sequentially capturing images of the inside of the subject by the capsule endoscope images of the inside of the subject, a first feature image representing a first feature and a second feature image representing a second feature, and that further extracts, from a second image group acquired before the first image group by sequentially capturing images of the inside of a subject identical to the subject, a third feature image representing the first feature and a fourth feature image representing the second feature; a feature data acquiring unit that acquires, a first feature data characterizing a movement of the capsule endoscope between the first feature image and the second feature image extracted from the first image group, and a second feature data characterizing a movement of the capsule endoscope between the third feature image and the fourth feature image extracted from the second image group; a comparing unit that compares the first feature data with the second feature data; and a display control unit that performs, with respect to the first image group, display control based on a result of the comparison by the comparing unit.