1. An image processing system comprising: a captured image acquiring section that acquires a captured image taken by an image capturing apparatus; a distance information acquiring section that acquires subject distance information that is information indicative of a distance between the image capturing apparatus and a subject for each of a plurality of partial areas in the captured image acquired by said captured image acquiring section; an image processing section that performs an image processing different from one another on each of the plurality of partial areas in the captured image acquired by said captured image acquiring section according to the subject distance information acquired by said distance information acquiring section; a boundary specifying section that specifies a boundary of a subject in the captured image acquired by said captured image acquiring section based on the subject distance information acquired by said distance information acquiring section, wherein said image processing section uses the boundary specified by said boundary specifying section to perform an image processing on the captured image acquired by said captured image acquiring section; and a main subject area specifying section that specifies a main subject area that is an area of a main subject included in the captured image acquired by said captured image acquiring section by means of the boundary specified by said boundary specifying section, wherein said image processing section performs an image processing different from each other on an image in the main subject area and an image in an area except the main subject area, said image processing section performs an image processing on the image in the area except the main subject area so as to have a color definition lower than that of the image in the main subject area, and said image processing section generates a new image in which only the main subject is emphasized by processing a captured image.