function showfoto(url, picwidth, picheight, description)
{
  var bigpicWin = null;
  if (!bigpicWin || bigpicWin.closed)
  {
    usrwidth = screen.width;
    usrheight = screen.height;

    winwidth = picwidth;
    winheight = picheight;

    var bron=url;

    var X = (usrwidth - winwidth) / 2;
    var Y = (usrheight - winheight) / 2;

    properties = "toolbar=no,location=no,directories=no,status=no,scrollbars=no,resizable=no,copyhistory=no,width="+winwidth+",height="+winheight+",";

    checkie = navigator.appName.indexOf("icrosoft");
    if (checkie == -1)
    {
      properties = properties+"screenX="+X+",screenY="+Y;
    }
    else
    {
      properties = properties+"left="+X+",top="+Y;
    }

    bigpicWin = window.open('','bigpicWin',properties);

    bigpicWin.document.open();
    bigpicWin.document.write('<HTML><HEAD>');
    bigpicWin.document.write('<TITLE>'+url+'</TITLE>');
    bigpicWin.document.write('<link href="opmaak.css" rel="StyleSheet" type="text/css" ></style>');
    bigpicWin.document.write('</HEAD>');
    bigpicWin.document.write('<BODY style="margin: 0pt;">');
    bigpicWin.document.write('<A HREF="JavaScript:self.close()"><IMG SRC="'+bron+'" HSPACE="0" VSPACE="0" ></A><br>');
    bigpicWin.document.write('<div class="onderschrift">'+description+'</div>');
    bigpicWin.document.write('</BODY>');
    bigpicWin.document.write('</HTML>');
    bigpicWin.document.close()

    bigpicWin.focus();
  }
  else
  {
    bigpicWin.focus();
  }
}

