A display device of the present invention displays a first image stored in first memory and a second image stored in second memory, by overlaying the first image on the second image. Once a display size/position of the first image is acquired, a first image generation unit is controlled to start generating the first image complying with the acquired display size/position. Until generation of the first image is completed, (i) a second image generation unit is controlled to generate an opaque second image that is opaque and large enough in size to cover the first image being generated, and (ii) the opaque second image is displayed. Upon completion of generation of the first image, (i) the second image generation unit is controlled to generate a partially transparent second image including a transparent part to be positioned over the first image, and (ii) the partially transparent second image is displayed.