function imageViewer( window_name, img_width, img_height, img_url, img_title, img_desc ) {
var win_width = img_width + 40;
var win_height = img_height + 90;
var win_top = ( screen.height - win_height ) / 2 - 4; // window borders approx.
var win_left = ( screen.width - win_width ) / 2 - 4;
win = window.open( "", window_name, "toolbar=no, directories=no, location=no, status=yes, menubar=no, resizable=yes, scrollbars=no, width=" + win_width + ", height=" + win_height + ", left=" + win_left + ", top=" + win_top );
win.document.write( "" );
win.document.write( "" + img_title + "" );
win.document.write( '' );
win.document.write( '' );
win.document.write( '' );
win.document.write( '' );
win.document.write( '' + img_desc + '
' );
win.document.write( "" );
win.document.close();
return false;
}