UOFiddler IS the right software.
Just right click the item you're going to change the graphic and click Replace. After that, right click on any item and click on Save. UOFiddler will probably ask for an output directory (if not, there should be an option for it on the preferences).
Thanks but this is exactly what I dont want to do
I want to save JUST a changes into a separate file (usualy Verdata.mul) and if someone wants to change just those items i modified then he will copy this Verdata.mul into UltimaOnline directory as well as VerdataPatcher.exe and once the verdatapatcher.exe is run it will patch the art.mul by my graphic in verdata.mul....
you can download those modifications everywhere...
thanks for reply how to do this