$re = '/\[picture\](?:([a-z][a-z\d+\-.]*:\/{2}(?:(?:[^\p{C}\p{Z}\p{S}\p{P}\p{Nl}\p{No}\p{Me}\x{1100}-\x{115F}\x{A960}-\x{A97C}\x{1160}-\x{11A7}\x{D7B0}-\x{D7C6}\x{20D0}-\x{20FF}\x{1D100}-\x{1D1FF}\x{1D200}-\x{1D24F}\x{0640}\x{07FA}\x{302E}\x{302F}\x{3031}-\x{3035}\x{303B}]*[\x{00B7}\x{0375}\x{05F3}\x{05F4}\x{30FB}\x{002D}\x{06FD}\x{06FE}\x{0F0B}\x{3007}\x{00DF}\x{03C2}\x{200C}\x{200D}\pL0-9\-._~\!$&\'()*+,;=:@|]+|%[\dA-F]{2})+|[0-9.]+|\[[a-z0-9.]+:[a-z0-9.]+:[a-z0-9.:]+\])(?::\d*)?(?:\/(?:[^\p{C}\p{Z}\p{S}\p{P}\p{Nl}\p{No}\p{Me}\x{1100}-\x{115F}\x{A960}-\x{A97C}\x{1160}-\x{11A7}\x{D7B0}-\x{D7C6}\x{20D0}-\x{20FF}\x{1D100}-\x{1D1FF}\x{1D200}-\x{1D24F}\x{0640}\x{07FA}\x{302E}\x{302F}\x{3031}-\x{3035}\x{303B}]*[\x{00B7}\x{0375}\x{05F3}\x{05F4}\x{30FB}\x{002D}\x{06FD}\x{06FE}\x{0F0B}\x{3007}\x{00DF}\x{03C2}\x{200C}\x{200D}\pL0-9\-._~\!$&\'()*+,;=:@|]+|%[\dA-F]{2})*)*(?:\?(?:[^\p{C}\p{Z}\p{S}\p{P}\p{Nl}\p{No}\p{Me}\x{1100}-\x{115F}\x{A960}-\x{A97C}\x{1160}-\x{11A7}\x{D7B0}-\x{D7C6}\x{20D0}-\x{20FF}\x{1D100}-\x{1D1FF}\x{1D200}-\x{1D24F}\x{0640}\x{07FA}\x{302E}\x{302F}\x{3031}-\x{3035}\x{303B}]*[\x{00B7}\x{0375}\x{05F3}\x{05F4}\x{30FB}\x{002D}\x{06FD}\x{06FE}\x{0F0B}\x{3007}\x{00DF}\x{03C2}\x{200C}\x{200D}\pL0-9\-._~\!$&\'()*+,;=:@\/?|]+|%[\dA-F]{2})*)?(?:#(?:[^\p{C}\p{Z}\p{S}\p{P}\p{Nl}\p{No}\p{Me}\x{1100}-\x{115F}\x{A960}-\x{A97C}\x{1160}-\x{11A7}\x{D7B0}-\x{D7C6}\x{20D0}-\x{20FF}\x{1D100}-\x{1D1FF}\x{1D200}-\x{1D24F}\x{0640}\x{07FA}\x{302E}\x{302F}\x{3031}-\x{3035}\x{303B}]*[\x{00B7}\x{0375}\x{05F3}\x{05F4}\x{30FB}\x{002D}\x{06FD}\x{06FE}\x{0F0B}\x{3007}\x{00DF}\x{03C2}\x{200C}\x{200D}\pL0-9\-._~\!$&\'()*+,;=:@\/?|]+|%[\dA-F]{2})*)?)|(www\.(?:[^\p{C}\p{Z}\p{S}\p{P}\p{Nl}\p{No}\p{Me}\x{1100}-\x{115F}\x{A960}-\x{A97C}\x{1160}-\x{11A7}\x{D7B0}-\x{D7C6}\x{20D0}-\x{20FF}\x{1D100}-\x{1D1FF}\x{1D200}-\x{1D24F}\x{0640}\x{07FA}\x{302E}\x{302F}\x{3031}-\x{3035}\x{303B}]*[\x{00B7}\x{0375}\x{05F3}\x{05F4}\x{30FB}\x{002D}\x{06FD}\x{06FE}\x{0F0B}\x{3007}\x{00DF}\x{03C2}\x{200C}\x{200D}\pL0-9\-._~\!$&\'()*+,;=:@|]+|%[\dA-F]{2})+(?::\d*)?(?:\/(?:[^\p{C}\p{Z}\p{S}\p{P}\p{Nl}\p{No}\p{Me}\x{1100}-\x{115F}\x{A960}-\x{A97C}\x{1160}-\x{11A7}\x{D7B0}-\x{D7C6}\x{20D0}-\x{20FF}\x{1D100}-\x{1D1FF}\x{1D200}-\x{1D24F}\x{0640}\x{07FA}\x{302E}\x{302F}\x{3031}-\x{3035}\x{303B}]*[\x{00B7}\x{0375}\x{05F3}\x{05F4}\x{30FB}\x{002D}\x{06FD}\x{06FE}\x{0F0B}\x{3007}\x{00DF}\x{03C2}\x{200C}\x{200D}\pL0-9\-._~\!$&\'()*+,;=:@|]+|%[\dA-F]{2})*)*(?:\?(?:[^\p{C}\p{Z}\p{S}\p{P}\p{Nl}\p{No}\p{Me}\x{1100}-\x{115F}\x{A960}-\x{A97C}\x{1160}-\x{11A7}\x{D7B0}-\x{D7C6}\x{20D0}-\x{20FF}\x{1D100}-\x{1D1FF}\x{1D200}-\x{1D24F}\x{0640}\x{07FA}\x{302E}\x{302F}\x{3031}-\x{3035}\x{303B}]*[\x{00B7}\x{0375}\x{05F3}\x{05F4}\x{30FB}\x{002D}\x{06FD}\x{06FE}\x{0F0B}\x{3007}\x{00DF}\x{03C2}\x{200C}\x{200D}\pL0-9\-._~\!$&\'()*+,;=:@\/?|]+|%[\dA-F]{2})*)?(?:#(?:[^\p{C}\p{Z}\p{S}\p{P}\p{Nl}\p{No}\p{Me}\x{1100}-\x{115F}\x{A960}-\x{A97C}\x{1160}-\x{11A7}\x{D7B0}-\x{D7C6}\x{20D0}-\x{20FF}\x{1D100}-\x{1D1FF}\x{1D200}-\x{1D24F}\x{0640}\x{07FA}\x{302E}\x{302F}\x{3031}-\x{3035}\x{303B}]*[\x{00B7}\x{0375}\x{05F3}\x{05F4}\x{30FB}\x{002D}\x{06FD}\x{06FE}\x{0F0B}\x{3007}\x{00DF}\x{03C2}\x{200C}\x{200D}\pL0-9\-._~\!$&\'()*+,;=:@\/?|]+|%[\dA-F]{2})*)?))\[\/picture\]/iu';
$str = '[picture]https://www.phpbb.com/assets/images/images/logo_phpbb.png?q=(v)[/picture]
';
preg_match($re, $str, $matches, PREG_OFFSET_CAPTURE, 0);
// Print the entire match result
var_dump($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