$(document).mouseover(function() { 
//Wallpaper HOVER 
$("#wallpaper-1").hover(
  function () {
    $(this).css({"z-index":"22"});
  }, 
  function () {
    $(this).css({"z-index":"21"});
  }
);
$("span#overlay-1").mouseleave(
  function () {
    $(this).css({"display":"none"});
  }
);
$("#wallpaper-2").hover(
  function () {
    $(this).css({"z-index":"22"});
  }, 
  function () {
    $(this).css({"z-index":"20"});
  }
);
$("#wallpaper-3").hover(
  function () {
    $(this).css({"z-index":"22"});
  }, 
  function () {
    $(this).css({"z-index":"19"});
  }
);
$("#wallpaper-4").hover(
  function () {
    $(this).css({"z-index":"22"});
  }, 
  function () {
    $(this).css({"z-index":"18"});
  }
);
});