An image processing system includes a plurality of MFPs (Multi Function Peripheral) connected to a network, and each of the plurality of MFPs is provided with an HDD (Hard Disk Drive) to store registered user information associating user identification information for identifying a user and personal information related to that user, and when the user identification information is inputted, it determines whether the personal information associated with the user identification information is stored in the HDD or not, and if the personal information is stored, the personal information is read from the HDD, and if the personal information is not stored, it transmits a personal information transmission request including the user identification information to another MFP, and receives the personal information from the MFP that stores the registered user information including the user identification information, and controls a prescribed apparatus operation based on the read or received personal information.