window.addEvent('domready', function() {

  $$('#menu_middle a').each(function(el){
     var tmp1 = new Element ( 'img' , { src : 'images/menu_middle/' + el.getText() + '.gif'  } ) ;
     var tmp2 = new Element ( 'img' , { src : 'images/menu_middle_hover/' + el.getText() + '.gif'  } ) ;
          
     el.onmouseover = function(){ 
        var img = this.getElements( 'img' ) ; 
        img[0].src = img[0].src.replace('menu_middle','menu_middle_hover');
       };
 
     el.onmouseout = function(){ 
        var img = this.getElements( 'img' ) ; 
        img[0].src = img[0].src.replace('menu_middle_hover','menu_middle');
       }; 
     
  });

});