$re = '/href=\"(.*?)\"/';
$str = '[<a class="lightbox" href="fileadmin/user_upload/images/Sprachen/Englisch/USA/San_Diego/San_Diego_EC/EC_San_Diego_Galerie.jpg" title=""><img alt="Sprachschule EC San Diego" border="0" height="80" src="typo3temp/pics/EC_San_Diego_Galerie_d1def1bf4a.jpg" title="Sprachschule EC San Diego (Copyright EC San Diego. All rights reserved.)" width="80"/></a>, <a class="lightbox" href="fileadmin/user_upload/images/Sprachen/Englisch/USA/San_Diego/San_Diego_EC/EC_San_Diego_Galerie-_1_.jpg" title=""><img alt="Sprachschule EC San Diego 2" border="0" height="80" src="typo3temp/pics/EC_San_Diego_Galerie-_1__fd87630014.jpg" title="Sprachschule EC San Diego 2 (Copyright EC San Diego. All rights reserved.)" width="80"/></a>, <a class="lightbox" href="fileadmin/user_upload/images/Sprachen/Englisch/USA/San_Diego/San_Diego_EC/EC_San_Diego_Galerie-_10_.jpg" title=""><img alt="Sprachschule EC San Diego 3" border="0" height="80" src="typo3temp/pics/EC_San_Diego_Galerie-_10__a8ed60c277.jpg" title="Sprachschule EC San Diego 3 (Copyright EC San Diego. All rights reserved.)';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
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