1. An image generation system comprising: a memory configured to store instructions; and at least one processor configured to execute the instructions to: acquire image information from an image sensor; determine whether or not a player has made a grasp preparation motion based on the image information, the processor processing an image corresponding to a hand of the player that has made the grasp preparation motion when the processor has determined that the player has made the grasp preparation motion; determine whether or not the player has made a grasp motion that follows the grasp preparation motion with one hand that is a right hand or a left hand based on the image information; determine whether or not the player has made a grasp-linked motion with the other hand based on the image information when the at least one processor has determined that the player has made the grasp motion with the one hand, the grasp-linked motion being a motion that follows the grasp motion; and generate an image based on the determination results of the grasp motion and the grasp-linked motion.