Q:

How to handle RSS data coming from WordPress for Joomla's RSS Module?

I am trying to develop Bootstrap's carousel module for news which are fetched from a remote website using its RSS feed for my Joomla 3.3.3 web site. It is a WordPress web site. I have added the following code to WP web site's theme/functions.php
function zkanoca_add_image_to_rss() {
    $thumb_id = get_post_thumbnail_id( get_the_ID() );
    if ( ! empty( $thumb_id ) ) {
        echo '<myimage>' . wp_get_attachment_url( $thumb_id ) . '</myimage>';
    }
}
add_action('rss2_item', 'zkanoca_add_image_to_rss');
add_action('rss_item', 'zkanoca_add_image_to_rss');

I now can see <myimage>[image_url]</myimage> line in the rss feed when I look at the source code. 
But I do not know how to handle it on Joomla's RSS feed module (mod_feed). 
I have tried to extract image url using
 $feed[$i]->myimage;

in a loop just like $feed[$i]->title; but did not work.
I call var_dump() function for an item but could not see a key element for <myimage> information.
I have found  /libraries/joomla/feed/parser/rss.php and then added 
protected function handleMyimage(JFeed $feed, SimpleXMLElement $el) {
        $feed->myimage = (string) $el;
    }

After that, I have modified /libraries/joomla/feed/feed.php 
// /libraries/joomla/feed/feed.php
protected $properties = array(
    'uri' => '',
    'title' => '',
    'updatedDate' => '',
    'description' => '',
    'categories' => array(),
    'contributors' => array(),
    'myimage' => '' //added this key
);

Then I added 
 // /libraries/joomla/feed/link.php line 60s
 public $myimage;

into JFeedLink class and modified 
// /libraries/joomla/feed/link.php line 90s
public function __construct($uri = null, $relation = null, $type = null, $language = null, $title = null, $length = null ) {
        $this->uri = $uri;
        $this->relation = $relation;
        $this->type = $type;
        $this->language = $language;
        $this->title = $title;

        // Validate the length input.
        if (isset($length) && !is_numeric($length)) {
            throw new InvalidArgumentException('Length must be numeric.');
        }
        $this->length = (int) $length;
    }

to 
// /libraries/joomla/feed/link.php line 90s 
public function __construct($uri = null, $relation = null, $type = null, $language = null, $title = null, $length = null,  /* added this */ $myimage = null /**/) {
        $this->uri = $uri;
        $this->relation = $relation;
        $this->type = $type;
        $this->language = $language;
        $this->title = $title;
        $this->myimage = $myimage; //added this line too

        // Validate the length input.
        if (isset($length) && !is_numeric($length)) {
            throw new InvalidArgumentException('Length must be numeric.');
        }
        $this->length = (int) $length;
    }

in /libraries/joomla/feed/link.php 
Output of an  is as the following
<item>
    <title>Title here</title>
    <link>http://example.com/?p=112</link>
    <comments>http://example.com/?p=112#comments</comments>
    <pubDate>Fri, 08 Aug 2014 06:05:56 +0000</pubDate>
    <dc:creator><![CDATA[Creator Information here]]></dc:creator>
    <category><![CDATA[General]]></category>
    <category><![CDATA[Arts]]></category>
    <guid isPermaLink="false">http://example.com/?p=112</guid>
    <description><![CDATA[ some text here [&#8230;]]]></description>
    <content:encoded><![CDATA[more text here]]></content:encoded>
    <wfw:commentRss>http://example.com/?feed=rss2&#038;p=112</wfw:commentRss>
    <slash:comments>0</slash:comments>
    <myimage>http://example.com/wp-content/uploads/2014/08/013.jpg</myimage>
</item>

A:

I was almost about to finish it with success :)
I have forgotten to add just one line into /libraries/joomla/feed/parser/rss.php 
protected function processFeedEntry(JFeedEntry $entry, SimpleXMLElement $el) {
        $entry->uri = (string) $el->link;
        $entry->title = (string) $el->title;
        $entry->publishedDate = (string) $el->pubDate;
        $entry->updatedDate = (string) $el->pubDate;
        $entry->content = (string) $el->description;
        $entry->guid = (string) $el->guid;
        $entry->comments = (string) $el->comments;

        //this line
        $entry->myimage= (string) $el->myimage;

Now, my problem has gone. 

