1. An image processing apparatus comprising: determination unit adapted to determine whether a presetting image which presets, as a composing target, a security image designated as a composing target for each of a plurality of images which are designated to be combined exists among said plurality of images; setting unit adapted to make setting to compose a security image with an image other than the presetting image and to output the composed image, when said determination unit determines that the presetting image exists; and a combining unit adapted to combine the image, which is set by said setting unit to compose with a security image and to output, with the presetting image.