A picture is worth a thousand words — and possibly several thousand dollars. Nicole Richie and rocker Joel Madden held their baby shower at the Beverly Hills Hotel last Sunday, with exclusive coverage granted to InStyle magazine. But early last week, pirated pics of “The Wizard of Oz”-themed party were being offered by a source to competing magazines. And one pal suspects Richie frenemy Paris Hilton might have had something to do with it. “All the photos that were offered had Paris right in the center of them, as the star,” sniffs the insider. “They look set up.”