To see the 3D effect : stare with the eyes at infinit , try to look trough and behind the image (do not focus on the image!) with the head level and try different distances. For me it works fine at a distance of 2 1/2 feet ( 75cm ), depending of the screen resolution you use . After a few seconds you see a third 3D image in between the two images. For unexercised eyes it can take up to 30 seconds but the result is stunning! If it doesn't work easily....make the images smaller by choosing medium size.