I never could see the images either. I tried unfocusing my eyes and crossing them, everything people say to try, but it never worked. A friend of mine has one that is framed with a sheet of glass in front. The trick he taught me was don’t look at the picture and to focus on my own reflection in the glass. I did that and I saw dinosaurs! It was the very first time I ever saw one of these work.

I still can’t see the one in this post though. I need the pane of glass to see my reflection to get it to work lol