this is what i use
(htaccess)
RewriteEngine On
RewriteCond %{HTTP_REFERER} ^http(s)?://(www\.)?images.google
RewriteCond %{REQUEST_URI} !googleimages.php
RewriteCond %{REQUEST_URI} (.*)
RewriteRule /* /googleimages.php?url=%1 [R,L]
(googleimages.php)
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html><head><title>Loading Site...</title>
<script language="JavaScript" type="text/javascript">
if (top.location != location) top.location.href = 'http://<? print $_SERVER["SERVER_NAME"] . $url;?>';
</script>
<script language="JavaScript" type="text/javascript">
<!-- Hide from old Browsers
if (top != self) top.location.href = location.href;
// Stop hiding from old browsers -->
</SCRIPT>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
</head>
<body>
<div align="center"><a href="http://<? print $_SERVER["SERVER_NAME"] . $url; ?>" target=_top class="style1">Click Here To Load The Site</a></div>
</body></html>