$re = '/\[\[file:(.*?(?:\.jpg|\.gif|\.bmp|\.png))(?:\||]).*/i';
$str = '[[File:EDI.png|thumb|304x304px|none]]
[[File:RMS Home screen.png|thumb|none]]
[[File:ClipCapIt-170110-133309.PNG]]
[[file:send-rec.jpg|thumb|none]]
[[file:send-rec.12412.2.123.jpg|thumb|none]]
[[file:send-rec.12412.2.123.jpg|thumb|none]]
[[file:send-rec.12412.2.123.not-jpg|thumb|none]]';
preg_match_all($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