1. An image processing device comprising: a composite processing unit that generates a composite image for display by including a through image generated based on a captured image signal obtained by performing photoelectric conversion for light incident from a subject in an image for a compositing process and composites a captured image of a recording time point in the image for a compositing process in accordance with a compositing arrangement state of the through image in the composite image for display; and a display control unit that performs display control for the composite image for display.