1. An image display system configured to display an image, comprising: an obtaining unit configured to obtain a surrounding image indicating surroundings of a vehicle; a plurality of detecting units disposed on the vehicle at different positions and configured to detect an object existing around the vehicle, respectively; an overlapping unit configured to overlap an indicator represented in the form of a frame with the surrounding image, the indicator indicating the object and a specific detecting unit which has detected the object from among the plurality of detecting units; and a display unit configured to display the surrounding image with which the indicator is overlapped.