Change navigation arrow image icons

[Nate]

I'm trying to replace the left and right arrow image icons. I tried to
replace fancy_nav_left.png and fancy_nav_right.png but had no luck.
Any ideas on how to do this?

[JFK]

those are used for IE6
fancybox uses a single sprite image (fancybox.png) for the rest of the
browsers

however, you don't need to modify this image, just play with css to
use your own images