1. A printing system in which an image sensing apparatus and printing apparatus directly communicate with each other, and said printing apparatus prints image data transmitted from the image sensing apparatus, wherein said printing apparatus comprises: first transmission means for transmitting function information of said printing apparatus from said printing apparatus to said image sensing apparatus after a protocol is established by applications installed in said printing apparatus and said image sensing apparatus; first reception means for receiving image data and information associated with a feature amount of the image from said image sensing apparatus; and correction means for correcting the image data received by said first reception means on the basis of the feature amount, and said image sensing apparatus comprises: second reception means for receiving the function information from said printing apparatus; feature amount extraction means for extracting a feature amount of a sensed image; and second transmission means for transmitting information associated with the feature amount extracted by said feature amount extraction means to said printing apparatus on the basis of the function information received by said second reception means.