$(document).ready(function(){
                     
                            $('#menu img').hover(function(){
                                   src = $(this).attr('class');
                                   if(src)
                                   {
                                          src = "http://r-studio.com.pl/cyfrowekadry/images/menu/"+src+'_hover.png';
                                          $(this).attr('src',src);
                                   }
                            },function(){
                                   src = $(this).attr('class');
                                   if(src)
                                   {
                                          src = "http://r-studio.com.pl/cyfrowekadry/images/menu/"+src+'.png';
                                          $(this).attr('src',src);
                                   }
                            })
                     
                     });

// Easing equation, borrowed from jQuery easing plugin
// http://gsgd.co.uk/sandbox/jquery/easing/
              $.easing.backout = function(x, t, b, c, d){
                     var s=1.70158;
                     return c*((t=t/d-1)*t*((s+1)*t + s) + 1) + b;
              };

jQuery(function( $ ){
       $('#slideshow').serialScroll({
              items:'li',
              prev:'a.prev',
              next:'a.next',
              offset:0, //when scrolling to photo, stop 230 before reaching it (from the left)
              start:0, //as we are centering it, start at the 2nd
              duration:1200,
              force:true,
              stop:true,
              lock:false,
              cycle:true, //don't pull back once you reach the end
              easing:'backout', //use this easing equation for a funny effect
              jump: false //click on the images to scroll to them
       });
       
});
        
        <!--
function displayWindow(url, width, height) {
        var Win = window.open(url,"displayWindow",'resizable=true,scrollbars=no,menubar=no' );
}
//-->