Abstract: A method of generating a representation of a subsidiary colored image initially contained within a color content of pixels of the image comprises defining a control data array. This control data array (9) defines, for at least those pixels in the image corresponding to the region containing the subsidiary image, the proportion of the image pixel color which is due to the subsidiary image. The average color in regions of the image different from the subsidiary image region is then determined. The inverse of the control data array is multiplied by the determined average color to generate a background image (13) which is subtracted (14) from the corresponding region of the original image so as to generate the representation of the subsidiary image.