Jwoww's legal fight with her ex-boyfriend ain't just about money -- TMZ has learned she's very concerned about some "derogatory" photos in his possession ... photos that we're told leave very little to the imagination.Weeks before the "Jersey Shore" star's ex-boyfriend/former business manager Thomas Lippolis sued Jwoww for allegedly stiffing him on several deals -- Jwoww's lawyer sent the guy a letter explaining a "final payment" for his services was in the works.