1. An image display device, comprising: a light source configured to provide a luminous flux; a plurality of light modulation devices configured to form a plurality of optical images through modulation of the luminous flux provided by the light source in accordance with image information, the light modulation devices being further configured to display an image by combining at least a portion of the optical images; a position change unit configured to move the optical images for position change; and a control unit configured to control the image display device, the control unit comprising: a characteristics acquisition section configured to acquire one or more characteristics of one or more of the optical images, the characteristics of the optical images including at least either an intensity of the optical images or a chromaticity of the optical images; a reference image setting section configured to designate one of the optical images as a reference image based on the acquired characteristics of the optical images and a remaining number of the optical images as non-reference images, the reference image setting section being configured to select, as the reference image, an optical image from within the optical images showing a largest value for the intensity or the chromaticity; and a position change unit control section configured to cause the position change unit to move the non-reference images in accordance with a pixel position of the reference image.