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: preparing image data representing an image including a plurality of regions; dividing the image into a plurality of band images each including at least one sub-region, the plurality of band images including a first band image and a second band image adjacent to the first band image; classifying each of the at least one sub-region included in the band image as one of an uniform sub-region and a nonuniform sub-region other than the uniform sub-region; creating region data used to identify each of the at least one sub-region included in the band image; updating the region data such that the region data identifies both a first uniform sub-region and a second uniform sub-region as a single uniform region of the image when the first uniform sub-region abuts the second uniform sub-region, the first uniform sub-region being included in the first band image and classified as the uniform sub-region, the second uniform sub-region being included in the second band image and classified as the uniform sub-region; and updating the region data such that the region data identifies both a first nonuniform sub-region and a second nonuniform sub-region as a single nonuniform region of the image when the first nonuniform sub-region abuts the second nonuniform sub-region, the first nonuniform sub-region being included in the first band image and classified as the nonuniform sub-region, the second nonuniform sub-region being included in the second band image and classified as the nonuniform sub-region.