Blinking is the second of two animation modes, which is selected in a very intuitive way. I tested blinking on two images : one made with AIPS IMAGR and the other with aips++ imager. The imaging was made as identical as possible. The biggest difference between the two was a 1 pixel offset in the coordinates. When blinking, the image pixels stayed aligned which meant that the image (and coordinate system) shifted back and forth by 1 pixel with each blink. Although the two images were registered, a given world coordinate blinks to a different position on the screen. Documentation is fine, but it would be nice to have a link from the top-level viewer URM page to the more practical hands-on documentation. Will discuss with David King when he returns.