1. An image display that displays a plurality of radiological images including the same photographic subject for comparison, comprising: a processor configured to: calculate a correction amount for matching the position or image quality of radiological images other than a reference radiological image among the plurality of radiological images with the position and/or image quality of the reference radiological image for each of the other radiological images; store the correction amount for each of the other radiological images so as to be associated with the reference radiological image; and generate an image based on the calculated correction amount.