The present invention provides easy operations of moving, rotating, magnifying, and reducing images displayed on a display screen attached to a computer by employing a selecting means. The selecting means having a function to communicate the computer via wireless means, which execute the following procedures to attains the objective of the present invention: detecting a relative position and a posture (a gradient) of itself, displaying the image on the screen in accordance with the moved position and the gradient, selecting the image displayed on the display attached to the computer and outputting (such as printing, etc.) the selected image.