1. An image processing apparatus comprising: an acquisition unit which acquires a first image group including plural images, the plural images obtained by sequentially photographing motion of an object; an area setting unit which sets plural areas at plural positions on each of the images of the first image group acquired by the acquisition unit; and a specifying unit which acquires pixel values of the plural areas set on each of the images by the area setting unit, and specifies a second image group including plural images relating to prescribed moments of motion of the object from among the first image group including plural images, based on change in the acquired pixel values of the plural areas.