1. An image processing apparatus comprising: generation means for generating image data; discrimination means for discriminating whether or not an externally connected equipment related to the image data generated by said generation means has a function of adding predetermined additional information to be hardly discernible by the human eye; adding means for adding the predetermined additional information to the image data generated by said generation means to be hardly discernible by the human eye in accordance with a discrimination result of said discrimination means; and output means for outputting the image data to which the predetermined additional information is added by said adding means or the image data generated by said generation means.