custom portable apps platform mods

I'd like to make a super custom Portable Apps Platform screen. can i add in an image and keep gradient changing ability? if not, does anypony know of a good editor that i can change the gradient to (from the silver one, preferably automatically) or have a vector drawing of it (so i can edit in inkscape portable)? and then put the picture in? also, can i change the paths that the buttons point to (like change document button to my school documents folder, or music to a music video folder inside a portable app's folder)?