Because the blink image is saved at the display server end of the X window system, it can be redisplayed much more quickly than the normal image drawing used by SAOimage. You will see the difference when you release the blinking button. To blink between saved images, press down on another mouse button, before releasing the earlier button.
The blinked image uses the existing color mapping. The colors are not restored to any previous setting. Therefore, one should keep the same color map settings when choosing displays for blinking, or manipulate the color map to find a setting which works for all of the blinking images.
Saved display images may all be of the current image, or, more likely, may be made from different, successively loaded images. The saved image can only be used for blinking. Displaying a saved image does not re-enable any other SAOimage functioning for that image. To be able to use the other functions on an image which is not the most recently read image, the image must must be reloaded from its file (or IRAF).
All saved displays must match the current display window dimensions. SAOimage unsaves all saved displays when the display window is resized.
Not all X servers are guaranteed to support display saving (called pixmaps). SAOimage will attempt to fall back on using image buffers within SAOimage for saving image displays. Unfortunately, some uncooperative X servers have been known to crash, rather than graciously decline the request. You will quickly know if you have such a server. Problems may also occur when the user tries to mix halftone and color pixmaps.