function ShowPic(picture)
{
var width = 840;
var height = 640;

var win_x = screen.availWidth/2 - width/2;
var win_y = screen.availHeight/2 - height/2;

Show=window.open(picture,'Show','toolbar=no,location=no,directories=no,status=yes,menubar=no,scrollbars=yes,resizable=yes,width='+width+',height='+height+',left='+win_y+',top='+win_x);
}