The present application generates an image in which a contour line is drawn about a tuned object in a virtual three-dimensional space. A reference width is stored in association with the tuned object. The reference width corresponds to a reference size of the tuned object. The reference size of the tuned object is a size of the tuned object when the tuned object is positioned a predetermined distance from a viewing point of a virtual camera. A line width of the contour line that is drawn about the tuned object is calculated based upon the reference width and a distance that the target object is positioned from the viewing point of the virtual camera.