$re = '@[\w,=/:.-]+\.(?:jpe?g|png|gif)@mu';
$str = '<a href="https://e...content-available-to-author-only...e.com/example1.jpg">
<a href="https://e...content-available-to-author-only...e.com/ストスト.jpg">
<a href="https://e...content-available-to-author-only...e.com/example3.jpg ';
preg_match_all($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