1. An image processing method comprising: obtaining input printing data that includes respective values for a plurality of pixels, wherein the input printing data includes image pixel data and character pixel data; identifying image pixels in the plurality of pixels in the input printing data; identifying character pixels in the plurality of pixels in the input printing data; selecting a first group of pixels in the input printing data, wherein the first group of pixels includes two or more image pixels and one or more character pixels, and wherein the first group of pixels is located at a first area in the plurality of pixels; generating a value for a first target pixel corresponding to the entire first area by generating an average value of the respective values of the two or more image pixels in the first group of pixels without using the respective values of any of the one or more character pixels in the first group of pixels, thereby generating reduced-resolution image pixel data; generating values indicating characters for second target pixels corresponding to the one or more character pixels in the first group of pixels and generating values for not indicating characters for third target pixels corresponding to an area of the two or more image pixels in the first group of pixels, wherein the values indicating characters and the values for not indicating characters are represented by fewer bits than the respective values of the plurality of pixel in the input printing data, thereby generating reduced-gradation-level character pixel data for a group of the second target pixels and the third target pixels corresponding to the entire first area, wherein a resolution of the reduced-gradation-level character pixel data is identical to a resolution of the input printing data, and wherein each of an area of the first target pixel in the reduced-resolution image pixel data and an area of the group of the second and third target pixels in the reduced-gradation-level character pixel data coincides with the first area in the plurality of pixels in the input printing data; generating first dot data based on the reduced-resolution image pixel data; generating second dot data based on the reduced-gradation-level character pixel data; and generating image print data by combining the first dot data and the second dot data.