To prompt secondary usage of saved images to improve use frequency of a service.

An image saving server provides the predetermined service to a customer (step ST11), determines whether points are used (step ST12), and subtracts used points corresponding to the predetermined service from present cumulative points when points are used (step ST13). It determines whether the cumulative points are smaller than zero (step ST14), sets a usage charge for the service at zero if the cumulative points are not smaller than zero (step ST15), and calculates the usage charge from the present cumulative points and sets the cumulative points to zero if the cumulative points are smaller than zero (step ST16).