var showing=false;

function showImage(src,width,height){
  var doc=document;
  var img=doc.getElementById('img');
  var box=doc.getElementById('box');
  img.src=src.replace('_thumb','');  
  showing=true;
}

function hideImage(){
  if(!showing){
    document.getElementById('box').style.display='none';
    document.getElementById('img').src='';
  }
  showing=false;
}

function moveImage(){
  var doc=document;
  var box=doc.getElementById('box');
  var img=doc.getElementById('img');
  
  if(doc.documentElement.scrollTop){
    var sl=doc.documentElement.scrollLeft;
    var st=doc.documentElement.scrollTop;
    }
  else{
    var sl=doc.body.scrollLeft;
    var st=doc.body.scrollTop;
  }
  
  box.style.display='';
  width=box.offsetWidth;
  height=box.offsetHeight;
  
  box.style.marginLeft=((doc.documentElement.clientWidth-width)/2)+sl+"px";
  box.style.marginTop=((doc.documentElement.clientHeight-height)/2)+st+"px";

}