A communication terminal, communicably connected with a service providing server, includes circuitry to receive a request for providing a service requested by a user, the service being one of one or more services provided by the service providing server; and perform a series of image processing on image data obtained at the communication terminal to implement the requested service in cooperation with the service providing server. In performing the series of image processing, the circuitry of the communication terminal executes a first program to perform first image processing on the image data, the first program requiring no authentication of the user in performing the first image processing, and executes a second program to perform second image processing on the image data, based on a determination that the user requesting the service is authorized to perform the second image processing.