Talk about paintings lining the walls! Here, they really did. After Louis Lima and Jerome Crepeau bought this barnlike house in 2002 and their renovation contractors began tearing out interior walls, they discovered 130 paintings on Upton board — many of them impressionistic “mudhead” portrait studies — nailed to the outside walls as insulation. These were a tangible reminder of the building’s history as a studio used by Henry Hensche (1901-1992), arguably first among equals of the disciples of Charles W. Hawthorne; then by James Kirk Merrick (1905-1985), a student of Hensche’s; and then by Lois Griffel, another Hensche student, who continued his Cape Cod School of Art nearby until 2000. Lima and Crepeau salvaged all but six of the paintings, which they left in situ as artistic Easter eggs, for the pleasure of a future owner to discover.