$re = '/&(amp|rs)[^"]+/';
$str = '<td><a href="https://mywebsite.com/book-234-god-is-one&rs=T&pi=DLaLVKLiMIagugSr9YFo&fed=0CBUQ9QEwAA&sdg=AFQjCNHwYLPqh3dXrKGaRucO6diyAt-hjQ"><img src="image.jpg"></a></td>';
$subst = "";
$result = preg_replace($re, $subst, $str, 1);
echo "The result of the substitution is ".$result;
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php