Graal shop problems..

[Gothika]

Whenever I try to gani a weapon or spell for my playerworld and I add the sprite to graal shop and Ive realised I forgot to set the transparacny.. So I add the trans and when I add the sprite again it still has no trans and nothing has changed.. Ive tryed changing the name of the file and when I add the sprite its blank so that means that gfx is now usless because I cant do anything with it in graal shop.
Am I doing somthing wrong here? I need help.