1. An image display device for displaying an image on the basis of image data comprising: an image feature quantity calculating portion which calculates a plurality of image feature quantities based on a luminance histogram of the image data; an expansion coefficient determining portion which determines an expansion coefficient based on the plurality of image feature quantities by referring to a predetermined expansion coefficient lookup table; and a luminance range expansion processing portion which performs a luminance range expansion process on the image data using the expansion coefficient, the luminance range expansion process being a process to extend a range of luminances of the image data.