I use Blink to select images from a set of 20. I zoom the viewer to look carefully at a single target star that I am studying and then as I click the mouse to advance to the next image I look to see if the star is still circular or oval due to a small tracking error or some atmospheric distortion. Currently I count the images, so I would say 1, then 2, then 3 etc and when I get to 20 I know I am on the last one. If I don't do this then I have to either leave the viewer and look at the image name or look over at the list to see which one is highlighted. Then go back to the viewer, click the mouse and look at the next image. I am hoping that it would be easy to add a toggle button with a semaphore attached to it so when the code gets to the last image, it would check the semaphore and if enabled it would wrap otherwise just sit on the last image. Needed only for convenience, not function.