function showPic(whichPic){
	var source = whichPic.getAttribute("href");
	var placeholder = document.getElementById("image-1");
	placeholder.setAttribute("src", source);	
  removeAllClasses();
  whichPic.className = whichPic.className + ' selected';
}

function removeAllClasses()
{
  $i = 0;
  var el;
  while($i < 100) {
    el = document.getElementById("button_" + ++$i);
    if (el)
    {
      el.className = null;
    } else {
      break;
    }
  }
  document.getElementById("button_" + --$i).className = 'last';
}