1. An image processing apparatus which performs an image modifying process with respect to an original image input via an image input section, comprising: a processing region setting section which sets a processing region in the original image input via the image input section; a sampling region specifying section which specifies a sampling region for forming a patch image applied to the processing region in the original image input via the image input section; a sampling region setting section which sets the sampling region specified by the sampling region specifying section; an image forming section which forms the patch image to be applied to the processing region set by the processing region specifying section based on the image of the sampling region set by the sampling region setting section; and an image editing section which replaces the image of the processing region in the original image input via the image input section by the patch image formed by the image forming section.