var step = 1

function IT1() {
 if(!document.images)
  return
  document.images.SK1.src=eval("pic1"+step+".src")
  document.images.SK2.src=eval("pic2"+step+".src")
  document.images.SK3.src=eval("pic3"+step+".src")

 if (step<3)
  step++
 else
  step=1
  setTimeout("IT1()",2500)
}

IT1()