A receiver image processing apparatus capable of easily performing post-processing in line with a print setting. The receiver image processing apparatus includes a printing unit able to print image data on a plurality of types of sheets of different sizes. When an incoming call arrives from a sender image processing apparatus, a determination unit of the apparatus determines whether a setting to perform post-processing on sheets by a post-processing unit has been made by a setting unit. If it is determined that the setting to perform post-processing has been made, a notification unit of the receiver image processing apparatus notifies size information representing a sheet size belonging to a predetermined series, as ability information of the apparatus, to the sender image processing apparatus.