1. A display device, comprising: an image processor to generate a first image to be displayed without overlapping a second image by processing an third image which would otherwise overlap the second image when displayed, the first image having a size that is smaller than the third image, wherein an aspect ratio of the third image is changed to generate the first image; a display unit to display the first image and the second image together, wherein the first image and the second image do not overlap when displayed; and a storage unit to store the third image.