1. An image processing method of applying an image processing to two dimensionally-arranged original image data corresponding to an entire image region of a photographed image including a main photographed-subject and producing output image data; comprising steps of: a region determining step of determining a main photographed-subject region of the main photographed-subject or a selected region by at least one on the two dimensionally-arranged original image data; a target region setting step of setting the entire image region and one of the main photographed-subject region and the selected region as target regions for an image processing; an image characteristic obtaining step of obtaining image characteristics from each of the target regions; an evaluation criterion calculating step of calculating a granularity value and a sharpness value for each of the target regions from the respective image characteristics of the target regions, wherein each of the granularity value and the sharpness value is an evaluation criterion standardized with a functional value; and an image processing step of conducting an image processing for the two dimensionally-arranged original image data with reference to the granularity value and the sharpness value.