1. An image processing apparatus comprising: a reception unit adapted to receive from a client, an image and an object included in the image; a storage unit adapted to store an operation environment of the client as metadata of the object included in the image; an evaluation unit adapted to evaluate an attribute of the object received by the reception unit; a recording unit adapted to, when an instruction is input to re-evaluate the attribute of the object which has undergone attribute evaluation by the evaluation unit, make as metadata a record indication that the attribute has been re-evaluated; and an execution unit adapted to, upon receiving another image different from the image, when an operation environment of a client which has instructed to perform image processing of the other image is identical to the operation environment of the client which is stored by the storage unit, and the record is in the recording unit indicating that the attribute has been re-evaluated, execute re-evaluation of attribute of the received other image.