$re = '/<img[^>]+src="http:\/\/www\.example\.org\/image_to_be_removed\.jpg"[^>]*\>/m';
$str = '<h1>Test article with HTML5 tags</h1>
<nav><a href="/link1/">Link 1</a></nav>
<p>This is an example article. The article may or may not include html5 tags, images and other things.</p>
<img src="http://www.example.org/image_to_be_removed.jpg">
<p>More example text.</p>';
preg_match_all($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