An image output apparatus includes: a memory configured to store user identification data; a receiver configured to receive image data and user identification data; an input unit by use of which a user inputs his/her user identification data; a clock; and an image forming unit that: if a time indicated by the clock is within a predetermined standby time, suspends outputting of an image represented by image data received by the receiver; and if user identification data input using the input unit during the predetermined standby time is stored in the memory, outputs an image represented by image data, which is associated with the input user identification data, from among items of image data received by the receiver and not yet output.