I need a script that allows a user to simply mouse-over a thumbnail which then updates a master image on the screen.

An example of what I mean can be seen on http://www.increation.net/bathrooms/gallery.htm

my page http://www.cataloguing.co.za/lbk/Finishes.htm needs to be in the format wrt grouping of similar finishes. Currently it works with a mouse click but I want it to work with mouseover and mouseout.

I have seached all over but cannot find anything suitable.