An image processing device includes a processor, and a memory storing computer-readable instructions therein. The computer-readable instructions, when executed by the processor, causes the image processing device to perform: generating edge image data by using the original image data; calculating characteristic values for a plurality of determination regions; and identifying a determination region as a nonuniform region when the characteristic value of the determination region satisfies a prescribed criterion, and the determination region as a uniform region when the characteristic value of the determination region does not satisfy the prescribed criterion. Each of the plurality of determination regions corresponds to one of the characteristic values, represents a part of the edge image, and includes a plurality of pixels, the plurality of determination regions being different from one another, each of the characteristic values characterizing the edge strength of the corresponding determination region.