#header-photos-links {
        background-image: url('stadtbuecherei_FILES/stadtbuecherei-links.jpg');
      }
      
      #header-photos-mitte {
        background-image: url('stadtbuecherei_FILES/stadtbuecherei-mitte.jpg');
      }
      
      #header-photos-rechts {
        background-image: url('stadtbuecherei_FILES/stadtbuecherei-rechts.jpg');
      }