An information processing system includes an operator terminal to transmit a captured image, and an image searching system connected with the operator terminal. The image searching system includes a first memory to store a registration image of a registration object and associated attachment information, and first circuitry configured to receive the captured image from the operator terminal, search the attachment information based the captured image, and transmit the attachment information. The operator terminal includes second circuitry to transmit the captured image to the image searching system, receive the attachment information from the image searching system, acquire a specific content from a storage location on a network in accordance with the received attachment information, execute a first application to perform a specific operation using the specific content, and execute a second application to call the first application when the received attachment information includes a text string designating the specific operation.