An image source apparatus includes: a driver, operable to send the image data to the printer and to cause the printer to execute the printing based on the image data, in accordance with a prescribed standard; an application processor; and a storage. When the driver receives an initialization request from the application processor, the driver, after notifying the application processor of an acknowledgement of the initialization request, carries out an initialization process in accordance with the received initialization request, and the driver, after finishing the initialization process, acquires information on a plurality of items related to a specification of the printer from the printer in accordance with the prescribed standard and stores the information in the storage. When the driver receives an acquisition command for acquiring any of the plurality of items from the application processor, the driver returns information on the item related to the acquisition command to the application processor with reference to the storage.