To realize an environment in which processing for comparing an image with another image can be executed while reducing an initial investment.

An image to be processed is compared with a reference image, and a large part of the difference between the images is detected as an error. When the error is detected, a billing amount to a user is determined so that the billing amount may be larger than a billing amount at a time when the error is not detected. Billing information indicating the billing amount is registered with a bill registration part in a server device, and the result of the comparison of the images is displayed together with the billing amount on the display part of a client device.