In an image printing apparatus for printing an image by combining dots of a plurality of sizes, a banding problem attributable to variations in conveying operation, and a temperature rise of a print head with an increase of the number of ejections are solved with a relatively simple configuration. To this end, a combination of dots of a plurality of sizes is assigned to each of pixels expressed at a plurality level of density. In this assignment, a dot larger than a pitch of an image resolution is preferentially allocated to a pixel having a density level higher than that to which one dot smaller than the pitch of the image resolution is allocated.