Aspects of the invention provide an image-display apparatus including an image display, such as a liquid-crystal display panel, where the image display can display a limited number of gray scales, interpolation is performed so that the number of gray scales displayed by the image display becomes the same as that of gray scales of obtained image data. The image-display apparatus can have the liquid-crystal display panel or the like and can be mounted on a mobile phone, a PDA, and so forth, so as to process and display image data transmitted from outside sources. First, a CPU performs a bit-slice process for the obtained image data, so as to reduce the data amount thereof. Next, a dither processing unit performs a dither process for interpolating the reduced data amount, so as to represent half-tone gray scales simulatively. In the invention, the dither process can be performed by using a 3.times.3 dither matrix for data whose gray-scale value corresponds to a predetermined area and a 2.times.2 dither matrix for data whose gray-scale value does not correspond to the predetermined area. Subsequently, the image display can display a predetermined image, where the number of gray scales of the predetermined image is the same as that of gray scales of the obtained data.