function random_imglink(){
  var img=new Array()
  img[1]="images/onbank/ib1.jpg"  
  img[2]="images/onbank/ib2.jpg"  
  img[3]="images/onbank/ib3.jpg"  
  img[4]="images/onbank/ib4.jpg"  


  var ry=Math.floor(Math.random()*img.length)

  if (ry==0)
     ry=1
     document.write('<img src="'+img[ry]+'" border="0" />')
}

  random_imglink()