It is the objective of the present invention to easily change between an image display application and the viewing of a program for a digital television, and to improve the usability of the television for operating an image display application. The display change list for a (channel) Up/Down key of a remote controller is dynamically altered so that, during the execution of an image display application, an application screen is displayed by using the Up/Down key. Further, when a memory card is loaded immediately after the television is powered on, a display application can be automatically activated. Furthermore, while a user is watching the television, the contents of a memory card is displayed on a small window in one part of the screen, and execution of the image application controlled by the user. In addition, no icons are displayed while an important program is on displaying. Moreover, since the same color and the same arrangement are used for the four function icons as are used for the four color keys on the remote controller, various processes can be performed for the image application.