An information processing system includes a vehicle, and a server configured to communicate with the vehicle. The vehicle generates a captured image of scenery outside the vehicle. The vehicle or the server: starts a first detection processing of successively detecting a first subject in the captured image; determines, as a target region, a partial region of the captured image including a prescribed number of first subjects when the prescribed number of the first subjects are detected; terminates the first detection processing of the target region; and performs image processing of lowering visibility of an image on the target region. The server then transmits the captured image subjected to the image processing to a transmission destination other than the vehicle.