A method for image data print control includes: obtaining subject image data which is obtained by capturing an image of a subject formed through a photographic optical system and output by an image-capturing element having a plurality of pixels; obtaining a distance to the subject; obtaining a number of pixels provided at the image-capturing element; obtaining a pixel pitch at the image-capturing element; obtaining a focal length of the photographic optical system; and calculating a printing resolution so as to print the image of the subject in a size equal to a size of the subject by using the subject image data, based upon the distance to the subject, the number of pixels at the image-capturing element, the pixel pitch at the image-capturing element and the focal length of the photographic optical system.