To provide an image forming system which enables a user to easily grasp information relevant to a photographic subject in an image formed on paper.

The image forming system comprises: image data of an image including a plurality of photographic subjects; a RAM 53 for storing information relevant to the plurality of photographic subjects; a detector 50b for detecting a position of a photographic subject in the image; a relevant information detector 50c for detecting information relevant to a photographic subject; a printing mechanism 57 for forming the image on paper P according to the image data; and a reader/writer 66 for writing the relevant information to an RF tag T added to the paper P so that the detected relevant information and a position of the photographic subject correspond to each other.