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