$re = '/ [0-9]{3}x[0-9]{3} /';
$str = 'kbksngklmdf from 555x666 to 666x444 Saving cfbhjnhguvfyr
kbksngklmdf from 555x666 to 666x444 Saving cfbhjnhguvfyrkbksngklmdf from 555x666 to 666x444 Saving cfbhjnhguvfyrkbksngklmdf from 555x666 to 666x444 Saving cfbhjnhguvfyrkbksngklmdf from 555x666 to 666x444 Saving cfbhjnhguvfyrkbksngklmdf from 555x666 to 666x444 Saving cfbhjnhguvfyrkbksngklmdf from 555x666 to 666x444 Saving cfbhjnhguvfyrkbksngklmdf from 555x666 to 666x444 Saving cfbhjnhguvfyr';
preg_match_all($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