function swapPic() 
 { 
 if(document.getElementById) 
   { 
   var thePicture=document.getElementById("my_banner"); 
   var picPath="http://www.ica-international.org/asmugmug/smugtitle-"+rnd(5)+".jpg"; 
   thePicture.style.background="url("+picPath+")"; 
   } 
 } 
  
function rnd(n) 
 { 
 return Math.floor(Math.random() * n) + 1; 
 }