<a href="#" onclick="window.open('img/1.jpg','gener','width=500,height=403,top=(screen.height-403)/2,left=(screen.width-500)/2,toolbar=no,location=no,directories=no,status=no,menubar=no,scrollbars=no,resiz
able=no')">

<a href="#" onclick="window.open('img/1.jpg','gener','width=500,height=403,top= ( screen.height - 403 ) / 2,left= ( screen.width - 500 ) / 2,toolbar=no,location=no,directories=no,status=no,menubar=no,scrollbars=no,resiz
able=no')">

<!--
function popup(url)
{
var width  = 500;
var height = 403;
var left   = (screen.width  - width)/2;
var top    = (screen.height - height)/2;
var params = 'width='+width+', height='+height;
params += ', top='+top+', left='+left;
params += ', directories=no';
params += ', location=no';
params += ', menubar=no';
params += ', resizable=no';
params += ', scrollbars=no';
params += ', status=no';
params += ', toolbar=no';
newwin=window.open(url,'windowname5', params);
if (window.focus) {newwin.focus()}
return false;
}
// -->
</script>
<a href="javascript: void(0)"
   onclick="popup('img/1.jpg')">center</a>