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 a recorded image for a compositing process and composites a captured image of a recording time point in the recorded image for the compositing process in accordance with an arrangement state of the through image in the composite image for display, wherein the recorded image is set as a background image in the composite image, wherein the composite processing unit performs a process of changing the background image based on a result of a comparison process between the through image and the background image, wherein the comparison process is a comparison process of image depth; and a display control unit that performs display control for the composite image for display.