An image processor generates an output image of a resolution higher than a resolution of an input image, using the input image. The image processor includes: an obtaining unit configured to obtain an edge strength of one of the input image and an image corresponding to the input image; a calculating unit configured to calculate, based on the edge strength, J that is a count of data items to be used for generating a synthesized image to be used in generating the output image, where J is an integer equal to or larger than 2; and a generating unit configured to generate the synthesized image by synthesizing J data items, and generate the output image using the synthesized image.