An image recording apparatus generates black, cyan, magenta, and yellow halftone image data from a multi-tone color image. When the cyan halftone image data is generated, the size of a cyan dot to be formed at a target pixel position is provisionally determined and added to the size of a black dot to obtain a total dot size. When the total dot size is less than or equal to a first threshold dot size, the cyan dot size is determined to be the provisionally determined size, and when the total dot size is greater than the first threshold dot size, the cyan dot size is determined to be the largest dot size within the range of a difference between the first threshold dot size and the black dot size. It is possible to prevent excessive overlapping of black and cyan dots.