1. An image processing device comprising: a processor; and a memory storing computer-readable instructions therein, the computer-readable instructions, when executed by the processor, causing the image processing device to perform: generating edge image data by using original image data, the edge image data representing an edge image that includes a plurality of pixels, each of the plurality of pixels having an edge strength; arranging a first determination region and a second determination region in the edge image, the first determination region and the second determination region having a same size, the first determination region having a first partial region, the second determination region having a second partial region, a position of the first partial region being the same as a position of the second partial region; creating a first characteristic value using edge strengths of a plurality of pixels arranged in the first determination region and a second characteristic value using edge strengths of a plurality of pixels arranged in the second determination region; determining whether the first characteristic value satisfies a prescribed criterion and whether the second characteristic value satisfies the prescribed criterion; and identifying: when the first characteristic value and the second characteristic value satisfy the prescribed criterion, the first determination region and the second determination region as a nonuniform region; when neither the first characteristic value nor the second characteristic value satisfies the prescribed criterion, the first determination region and the second determination region as a uniform region; when the first characteristic value satisfies the prescribed criterion and the second characteristic value does not satisfy the prescribed criterion, the first determination region except the first partial region as the nonuniform region, the second determination region except the second partial region as the uniform region, and the first partial region as a specific one of the nonuniform region and the uniform region; and when the first characteristic value does not satisfy the prescribed criterion and the second characteristic value satisfies the prescribed criterion, the first determination region except the first partial region as the uniform region, the second determination region except the second partial region as the nonuniform region, and the first partial region as the specific one of the nonuniform region and the uniform region.