An information processing device, an information processing system, an information processing method, and a program capable of appropriately reducing the amount of information of an image are provided. An information processing device includes an image acquisitor, an information amount reduction degree determiner, and an information amount reducer. The image acquisitor acquires an image acquired by imaging an actual space. The information amount reduction degree determiner determines a degree of reduction of an amount of information on the basis of an attribute of a subject shown in the image. The information amount reducer generates information reduced data acquired by reducing at least a part of the amount of information of the image in accordance with the degree of reduction of the amount of information.