[SOLVED] Can someone please help me with transitions for all images

I am trying to create the same transition affect for all images as coded by default for thumbnails. In other words I would like all images appear to appear gray scale until hovered over. I downloaded the CSS3 Transitions plug-in but I couldn't get that to work either. Here is a sample page that I would like to have treated in this way: http://tinyurl.com/o9p2fgp

Really would appreciate a push in the right direction.

Thanks in advance

AmiG.