IMAGE PROCESSING APPARATUS, CONTROL METHOD THEREFOR, PROGRAM, STORAGE MEDIUM, AND IMAGE CAPTURING APPARATUS

There is provided an image processing apparatus which corrects a shot image, which is shot by an image capturing apparatus and on which a shadow of a foreign substance existing on a shooting optical path of the image capturing apparatus is captured, so as to reduce an influence of the shadow of the foreign substance. The image processing apparatus includes a display unit which displays the shot image, a correction unit which corrects the shot image so as to reduce the influence of the shadow of the foreign substance on the basis of foreign substance information, an input unit which is used by a user to perform input operation in accordance with a shot image displayed on the display unit and inputs unregistered foreign substance information which has not been registered in foreign substance information, and an additional registration unit which additionally registers the unregistered foreign substance information.