How to replace the fade-wipe effect with a fade-in effect in Image Thumbnail ViewerII

[qwerty1234]

First of all sorry for my bad english... i'm an italian user.

For my website i'm using "Image Thumbnail Viewer II" script that works perfectly... unfortunately, the "fade-wipe effect" do not work with Firefox.

My question:

it's possible to replace this effect, that it works only in IE5.5+, with, e.g., a simple fade-in effect with a preloading image like this:
http://maximo71.altervista.org/temp/preloadingGIF.htm

if it's possible, someone could say me how to modify the script.

Thanks,
Max