need hack background

ok, im in the middle of making a hack, and im wandering how do i make the background for hack [this hack isnt for mw2, but there wasnt a link for this game]...yeah so i need help on making the background, what program do i use, and how do i open it in the program..

-please send back.
-hack is for bioshock, and i chose this website cuz its most known for hacks.