An overall controller of a console acquires a radiation image of an imaging subject captured by a radiation image capture device for radiographic imaging. The overall controller also acquires body thickness information indicating a body thickness of the imaging subject in a direction in which radiation passes through. The overall controller also adds to the radiation image an assist line image that have would be expected to be obtained if a predetermined member had been disposed and captured at a position inside the imaging subject determined based on the acquired body thickness information, or at a position between the imaging subject and the radiation image capture device.
