<?php
$html = <<<DATA
<body>
<h1>Text 1<img title="Not this"></h1>
<h2>Text 2<img title="Not this"></h2>
<h3>Text 3<img title="This"></h3>
</body>
DATA;
$dom = new DOMDocument('1.0', 'UTF-8');
$dom->loadHTML($html, LIBXML_HTML_NOIMPLIED | LIBXML_HTML_NODEFDTD);
$xpath = new DOMXPath($dom);
$imgs = $xpath->query('//h3/img[@title]');
foreach($imgs as $img) {
}
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