An image display apparatus can include a display; an image receiver to receive a broadcast signal; a signal processing device to output an image signal based on the broadcast signal; and an interface to exchange data with a mobile terminal or a server Also, the signal processing device is configured to display a plurality of broadcast channel thumbnails, and in response to receiving a selection of one of the plurality of broadcast channel thumbnails, obtain a broadcast image corresponding to the selected broadcast channel thumbnail from the image receiver, receive chatting conversation content corresponding to the broadcast image from the server, and overlay the chatting conversation content on the broadcast image. Also, the signal processing device is configured to in response to receiving input conversation content based on a signal from a remote controller, display the input conversation content together with the broadcast image and the chatting conversation content.