1. An image processing apparatus comprising: a combination unit that combines a first image to a M-th (M≧2) image to generate a (M+1)-th image; and a processing unit that compares security levels of a first security image to a M-th security image which are set in order to protect securities of the first image to the M-th image respectively, and composing a security image having highest security level with the (M+1)-th image.