$re = '/-\h*(?!.*-)0*(\d+)/m';
$str = '“2020-07-24 07;17;09 - ABCD - 12345-67890 (14 Main St) - 01 [Declaration 1].png”
“2020-07-24 07;17;09 - ABCD - 12345-67890 (14 Main St) - 02 [Declaration 2].png”
“2020-07-24 07;17;09 - ABCD - 12345-67890 (14 Main St) - 07 [Fire].png”
“2020-07-24 07;17;09 - ABCD - 12345-67890 (14 Main St) - 12 [Fungi etc].png”';
preg_match_all($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