Parsing RSS Feed For Images

I’m trying to parse out an RSS feed for images. My original code grabbed the title, description, link, and pubDate just fine. I read a tutorial online on how to get the images out as well, but now that I’ve updated my pull it gives me the errror:
Fatal error: Call to a member function getAttribute() on a non-object in /home/ode/public_html/dev/cron-insights2.php on line 10

Here was my original code:

<?php

$rss = new DOMDocument();
$rss->load('http://feeds.feedburner.com/feedburner/Dvzy?format=xml');
$feed = array();

//FOR EACH ITEM RETURN RSS
foreach ($rss->getElementsByTagName('item') as $node) {

    $img = $rss->getElementsByTagName('img')->item(0)->getAttribute('src');

    $item = array(
        'title' => $node->getElementsByTagName('title')->item(0)->nodeValue,
        'desc' => $node->getElementsByTagName('description')->item(0)->nodeValue,
        'link' => $node->getElementsByTagName('link')->item(0)->nodeValue,
        'date' => $node->getElementsByTagName('pubDate')->item(0)->nodeValue,
        'image' => $img,
    );
    array_push($feed, $item);
}

echo '<pre>';
var_dump($feed);
echo '</pre>';

I was able to fix the issue by tweaking the code below:

<?php 

error_reporting(E_ALL);
echo '<meta charset="utf-8" />';
echo '<pre>';

$url = 'http://feeds.feedburner.com/feedburner/Dvzy?format=xml';
$xml = file_get_contents($url);
$xml = str_replace('<content:encoded>', '<content_encoded>', $xml);
$xml = str_replace('</content:encoded>', '</content_encoded>', $xml);
$obj = SimpleXML_Load_String($xml, 'SimpleXMLElement', LIBXML_NOCDATA);

// ACTIVATE THIS TO SEE THE XML
// echo htmlentities($xml);

// ACTIVATE THIS TO SEE THE OBJECT
// var_dump($obj);

// COLLECT INFORMATION HERE
$feed = [];

// A REGEX THAT FINDS IMAGE TAGS SRC ATTRIBUTE
$rgx
= '~'                  // REGEX DELIMITER
. 'src="'              // SRC INSIDE IMAGE TAG
. '('                  // START CAPTURE GROUP
. '[^"]*'              // ANYTHING UP TO END
. ')'                  // ENDOF CAPTURE GROUP
. '"'                  // END OF SRC ATTRIBUTE
. '~'                  // REGEX DELIMITER
. 'i'                  // FLAG: CASE INSENSITIVE
. 's'                  // FLAG: SINGLE LINE
;

foreach ($obj->channel->item as $item)
{
    $node['title'] = (string)$item->title;
    $node['desc']  = (string)$item->description;
    $node['link']  = (string)$item->link;
    $node['date']  = (string)$item->pubDate;

    $content       = $item->content_encoded;
    preg_match_all($rgx, $content, $match);
    $node['image'] = $match[0][0];
    $feed[] = $node;
}
var_dump($feed);