It was more the rollover effect within the thumbnail. I guess the effect would be once the mouse button is hovered over the thumbnail a png image appears illustrating a small magnifying glass.
It creates a span with the magnifying glass image in it, and when you hover on the image, the script makes the image go from opacity:1 to opacity:0.2, so the mag glass image is seen.
JS isn’t my area, though, so unless you can play with these scripts yourself, someone else will have to give you further help!