An image processing program causing a computer to function as:
- an N-ary data generating unit that N-arizes (N≧2) image data, which is a set of M-ary pixel values (M>N) forming an image, for each pixel and generates N-ary image data;
- and
- a print data generating unit that generates print data in which a dot size corresponding to each of the pixel values of the N-ary image data generated by the N-ary data generating unit is set;
- the program also causing the print data generating unit to function, if a dot size of a predetermined range continues in the print data, to generate print data in which the dot size corresponding to one of the pixels of the continuous dots is changed.