$re = '/<div class="listing-img-container media-cover text-center">[\s\S]*?src="([^"]+?\.jpg)/';
$str = '<div class="panel-image listing-img">
<a href="/rooms/854260?s=BD20" class="media-photo media-cover">
<div class="listing-img-container media-cover text-center">
<img itemprop="image" data-current="0" src="https://a2.muscache.com/ic/pictures/19208233/4d8e6c0d_original.jpg?interpolation=lanczos-none&size=x_medium&output-format=jpg&output-quality=70"
class="img-responsive-height" alt="Cozy room - Prague centre Old Town" data-urls="[output-format=jpg&output-quality=70", "https://a1.mu "ut-format=jpg&output-quality=70"]">
</div>';
preg_match_all($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