An image forming apparatus including an image acquisition section which acquires a color image; a memory section which stores a first table correlating a specific color with a symbol indicating the specific color; a color discrimination section which discriminates a color on the basis of color information of each portion in the color image, and extracts an area having the specific color; a symbol composition section which specifies the symbol corresponding to the specific color by reference to the first table, and composes the specified symbol into the area having the specific color in the color image to generate a composite color image; and an image output section which outputs the composite color image.