Police say they arrested a teenager after seeing photos of him with drugs and guns on his Facebook page, along with a posting suggesting that he would deliver marijuana to any buyer. Police said they got a search warrant and raided 19-year-old Darren Main Jr.’s home in the Manton neighborhood Monday. Officers said they seized two firearms and more than two dozen bags of marijuana. Main is being held without bail on drug and gun charges. Authorities said Main called himself ‘‘IPlead ThePiff’’ on Facebook and suggested in postings that he was in a gang.