$re = '/https?:\/\/(\w+\.)?imgur.com\/(\w*\d\w*)+(\.(png|jpg|gif|PNG|JPG|GIF|jpeg))?/i';
$str = '
https://imgur.com/gallery/kbRSjdw
test
https://i.imgur.com/zeOe49Q.jpeg
https://i.imgur.com/2M7LmOO.png';
preg_match_all($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