The present invention provides an image processing device and method for effectively generating a difference image from plural images. The plural images generated by an image generation unit are first associated with radiography date and hour information and stored in a storage unit, at least one reference image and one comparison image are designated by an image designation unit from the stored images, the date and hour information of the designated reference image is compared with that of the designated comparison image by an image comparison unit, a difference process is executed by a difference processing unit based on an operation determined based on the comparison result, and the processed difference image is displayed on a display unit under the control of a display control unit.