Return Largest Image

<?php
class Functions{
    /*
     * @author - Matt Cain from www.caincode.com
     * (Edited to fit purpose)
     */
    public function scrapeLargestImage($url) {
        // Returns the page content
        $page = file_get_contents($url);

        //Makes sure the page is not null
        if (!$page) {
            return false;
        }

        // Works with internal errors in libxml (basically hides those errors)
        libxml_use_internal_errors(true);

        /*Creates a new document, and loads it from the URL
         * Then returns all img elements */
        $dom = new DOMDocument;
        $dom->loadHTML($page);
        $imgs = $dom->getElementsByTagName('img');
        $imgsVisited = array();
        $maxLen = 0;
        $largest = '';

        // Iterates through each image on the page
        foreach ($imgs as $img) {

            //Returns the image attribute
            $src = $img->getAttribute('src');

            //Checks if the image is null or has been visited
            if (!empty($src) && !isset($imgsVisited[$src])) {
                $imgsVisited[$src] = true;
                $ch = curl_init($src);
                curl_setopt($ch, CURLOPT_NOBODY, true);
                curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
                curl_setopt($ch, CURLOPT_HEADER, true);
                curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true);
                $data = curl_exec($ch);
                curl_close($ch);
                if ($data === false) {
                    continue;
                }
                /* Sets image length to contentLen, then checks if
                 * contentLen is larger than the lax length*/
                $contentLen = 0;
                if (preg_match('/Content-Length: (\d+)/', $data, $matches)) {
                    $contentLen = (int)$matches[1];
                }
                if ($contentLen > $maxLen) {
                    $maxLen = $contentLen;
                    $largest = $src;
                }
            }
        }

        //Checks if there is a largest image, returns it's src attribute if so
        if (!empty($largest)) {
            return $largest;
        } else {
            return false;
        }
    }
}
?>