An image processing apparatus embeds decision information that is information about a specific parameter, such as degree of alteration, of an image, into an image signal, and sends the image signal to an external device, such as personal computer, for storage etc. When the image processing apparatus receives the image signal with the decision information embedded in it, the image processing apparatus extracts the decision information from the image signal, determines degree of alteration of the image based on the decision information extracted, sets an image processing parameter based on the degree of alteration determined, and subjects the image signal received to image processing based on the image processing parameter set.