XML Gallery: Fade Out image before loading next

How can I fade out the last image before calling the preloader for the next. I don’t like the way the current XML gallery (originally a kirupa tut) simply unloads the current image before calling the preloader for the new picture.

I’d like everything to fade in and out nicely.

Please see the attched ZIP file (the gallery is of my cat Gizmo if the name of the ZIP is confusing).

Thanks to anyone that can provide an answer or point me in the right direction!

http://www.designgeezer.com/kirupa/gizmo.zip