// show large thumbnail when mouseover in portfolio
function portShowBig(iObj){
  bt = $('bigThumb');
  bt.src = iObj.src.replace(/small/, 'large');
  x = findPosX(iObj);
  y = findPosY(iObj);
  bt.style.top = y;
  bt.style.left = (x-500);
  Element.show(bt);
  
}

function portHideBig(){
  Element.hide('bigThumb');  
}