A method for controlling an image display apparatus includes determining a type of a video signal included in an input signal, determining whether three-dimensional (3D) format information is included in the input signal, if the video signal is a 3D video signal, requesting 3D format information about the video signal to a server that stores 3D format information, if the input signal does not include the 3D format information about the video signal, and processing, upon receipt of 3D format information from the server in response to the 3D format information request, the video signal according to the 3D format information and displaying a 3D image based on the processed video signal.