reading more on this. I found from this site: That Texas Magazine - Articles

"..creates a haunted version of the image by manipulating a scan of the original photo using Adobe Photoshop. Both images are digitally cut into thin strips, stitched together (or interlaced) and printed on high quality paper. Finally, the lenticular lens is applied like a laminate over the composite image to create the shifting effect."

So, where do you get the Lenticular Lenses?