Mouseover greyscale without dupe images aanndd not interfering with java arrows

the page

www.philipdusel.com/hoy.html

has a mouseover greyscale effect on the thumbnails…i want that but the nav arrows in between the large img on left and thumnails do not change the large colored img to another large colored img when clicked…it changes to a large greyscale img. i know that this is currently a java issue but can and should this be done w css

:nono:
thanks