$re = '/(.*\.)(jpe?g|gif|docx?|pdf)$/mi';
$str = 'any_file_name_we_wish_here_with_!@#$%^&*_1234567.jpg
any_file_name_we_wish_here_with_!@#$%^&*_1234567.jpeg
any_file_name_we_wish_here_with_!@#$%^&*_1234567.JPG
any_file_name_we_wish_here_with_!@#$%^&*_1234567.docx
any_file_name_we_wish_here_with_!@#$%^&*_1234567.doc
any_file_name_we_wish_here_with_!@#$%^&*_1234567.pdf
any_file_name_we_wish_here_with_!@#$%^&*_1234567.gif
any_file_name_we_wish_here_with_!@#$%^&*_1234567.mp3
any_file_name_we_wish_here_with_!@#$%^&*_1234567.mp4';
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