$re = '/Need to process image tag.*\?custId=(\d+)/m';
$str = 'Need to process image tag <img src=\\"http://danny.oz.au/p/56214815-tripod.jpg?custId=1235\\"/>
Need to process image tag <img src=\\"http://danny.oz.au/p/56214815-tripod.jpg?custId=123445\\"/>';
preg_match_all($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