METHOD FOR CONTROLLING (A) IMAGE OF (AN) IMAGE DISPLAY DEVICE

An image control method in an image display device is provided to output a normal image through optimization when a frequency is forcedly adjusted so that synchronization destruction can be prevented and an image flicker can be prevented. An image control method comprises the following steps. It is determined whether a predefined number of input lines or more are continuously input in a normal state at the time of forced frequency adjustment(S101~S103). If a predefined number of input lines or more are continuously input, an associated cause is analyzed. An image is optimized according to an analysis result(S104). When four or more input lines are continuously input, an operating state is determined to be the normal state. The image is optimized by refreshing an image flicker detection threshold value, an active start value and a stop value.