1. A vehicle image display apparatus, comprising: a control unit configured to: acquire a plurality of captured images of an area around a vehicle, the plurality of captured images being captured by a plurality of cameras that are mounted on the vehicle at a plurality of positions; generate a single image that shows a state of the vehicle and a state around the vehicle using the plurality of captured images so acquired; display a composite image on a monitor after an input operation is given to an ignition switch of the vehicle, the composite image including the single image superposed with a first image showing boundary regions between the plurality of captured images in the single image and superposed with a second image showing end regions of the vehicle; highlight the first and second images for a time period after a start of display of the composite image; and non-highlight the first image and highlight the second image after the time period elapses.