$re = '/<meta.*property="og:image".*content="(.*)".*\/>/';
$str = '<meta property="og:image" content="http://www.moneycontrol.com/news_image_files/2013/s/Syrian_diesel_trucks_190.jpg" />';
preg_match($re, $str, $matches, PREG_OFFSET_CAPTURE, 0);
// Print the entire match result
var_dump($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