An image forming system includes a mobile terminal apparatus and an image forming apparatus. The mobile terminal apparatus displays a captured image of an operation panel of the image forming apparatus, extracts from the captured image, in response to a user operation on the captured image, an operation partial image including an operation part designated by the user operation, and transmits operation partial image data indicating the operation partial image to the image forming apparatus. The image forming apparatus identifies the operation part corresponding to the operation partial image data received from the mobile terminal apparatus, and executes an action corresponding to the identified operation part.