An image processing apparatus includes a color information generating unit that generates information of color values in input image data; an Index table generating unit that generates an Index table in which a first identification information according to a hash value is associated with a first predetermined number of color values; a drawing unit that generates a second identification information according to the hash value for each color value in the input image data and performs, when the second identification information is different from the first identification information associated with a color value in the Index table having a same value, drawing according to the color value, and when the second identification information is the same as the first identification information, drawing according to the first identification information; and a converting unit that converts an image drawn by the identification information into a color value.