Abstract: The invention relates to a display method for an image-generation means making it possible to protect a screen of a viewing device against freezing of the image, characterized in that the image-generation means continually and alternately displays during the operation of the said viewing device a first sub-image and a second sub-image the first sub-image comprising a warning message and the second sub-image being the negative image of the first sub-image, the frequency of the display being sufficiently high to hide the warning message and when the viewing device sustains a failure causing the freezing of the image, the image-generation means permanently displays the warning message according to the last sub-image displayed on the screen. The invention applies particularly to the aviation field and more generally to any field in which a frozen image failure of a screen is critical.