#iec-random {
  margin: 0 auto;
  position: relative;
  overflow:hidden;
  width:200px;
  height:200px;
  display:block;
}
	  
 #iec-random img{
  position: absolute;
  visibility:hidden;
  left: 0;
  top: 0;
}

 #iec-random img.active{
  visibility:visible; 
}