$re = '/(<img[^>]*?photobucket.*?>)/mi';
$str = '<img src="/photobucket/img21.png">
Do Not Want:
<img src="/imgs/test.jpg">
<img src="/imgs/thiswillgetpulledtoo.jpg"><p>We like photobucket</p>
<img src="/photobucket/img21.png">';
preg_match_all($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