An electronic device includes controller that generates, as a first image, an image in which a second display object is disposed in a region that is on a layer lower than a topmost layer and that is identical to a display region of a second image of a synthetic image while image superimposing unit is outputting synthetic image signal to display, monitors a change in color of an image within the region where the second display object is disposed in the first image, and changes a display form of the synthetic image upon detection of the change in color.