How can I fetch images with RSS?

<?php if (!defined('BASEPATH')) exit('No direct script access allowed');
class RSSParser {

    public $feed_uri            = NULL;                     // Feed URI
    public $data                = FALSE;                    // Associative array containing all the feed items
    public $channel_data        = array();                  // Store RSS Channel Data in an array
    public $feed_unavailable    = NULL;                     // Boolean variable which indicates whether an RSS feed was unavailable
    public $cache_life          = 0;                        // Cache lifetime
    public $cache_dir           = './application/cache/';   // Cache directory
    public $write_cache_flag    = FALSE;                    // Flag to write to cache
    public $callback            = FALSE;                    // Callback to read custom data


    function __construct($callback = FALSE)
    {
        if ($callback)
        {
            $this->callback = $callback;
        }
    }

    // --------------------------------------------------------------------

    function parse()
    {
        // Are we caching?
        if ($this->cache_life != 0)
        {
            $filename = $this->cache_dir.'rss_Parse_'.md5($this->feed_uri);

            // Is there a cache file ?
            if (file_exists($filename))
            {
                // Has it expired?
                $timedif = (time() - filemtime($filename));

                if ($timedif < ( $this->cache_life * 60))
                {
                    $rawFeed = file_get_contents($filename);
                }
                else
                {
                    // So raise the falg
                    $this->write_cache_flag = true;
                }
            }
            else
            {
                // Raise the flag to write the cache
                $this->write_cache_flag = true;
            }
        }

        // Reset
        $this->data = array();
        $this->channel_data = array();

        // Parse the document
        if (!isset($rawFeed))
        {
            $rawFeed = file_get_contents($this->feed_uri);
        }

        $xml = new SimpleXmlElement($rawFeed);

        if ($xml->channel)
        {
            // Assign the channel data
            $this->channel_data['title'] = $xml->channel->title;
            $this->channel_data['description'] = $xml->channel->description;

            // Build the item array
            foreach ($xml->channel->item as $item)
            {
                $data = array();
                $data['title'] = (string)$item->title;
                $data['description'] = (string)$item->description;
                $data['pubDate'] = (string)$item->pubDate;
                $data['link'] = (string)$item->link;
                $dc = $item->children('http://purl.org/dc/elements/1.1/');
                $data['author'] = (string)$dc->creator;

                if ($this->callback)
                {
                    $data = call_user_func($this->callback, $data, $item);
                }

                $this->data[] = $data;
            }
        }
        else
        {
            // Assign the channel data
            $this->channel_data['title'] = $xml->title;
            $this->channel_data['description'] = $xml->subtitle;

            // Build the item array
            foreach ($xml->entry as $item)
            {
                $data = array();
                $data['id'] = (string)$item->id;
                $data['title'] = (string)$item->title;
                $data['description'] = (string)$item->content;
                $data['pubDate'] = (string)$item->published;
                $data['link'] = (string)$item->link['href'];
                $dc = $item->children('http://purl.org/dc/elements/1.1/');
                $data['author'] = (string)$dc->creator;

                if ($this->callback)
                {
                    $data = call_user_func($this->callback, $data, $item);
                }

                $this->data[] = $data;
            }
        }

        // Do we need to write the cache file?
        if ($this->write_cache_flag)
        {
            if (!$fp = @fopen($filename, 'wb'))
            {
                echo "RSSParser error";
                log_message('error', "Unable to write cache file: ".$filename);
                return;
            }

            flock($fp, LOCK_EX);
            fwrite($fp, $rawFeed);
            flock($fp, LOCK_UN);
            fclose($fp);
        }

        return TRUE;
    }

    // --------------------------------------------------------------------

    function set_cache_life($period = NULL)
    {
        $this->cache_life = $period;
        return $this;
    }

    // --------------------------------------------------------------------

    function set_feed_url($url = NULL)
    {
        $this->feed_uri = $url;
        return $this;
    }

    // --------------------------------------------------------------------

    /* Return the feeds one at a time: when there are no more feeds return false
     * @param No of items to return from the feed
     * @return Associative array of items
    */
    function getFeed($num)
    {
        $this->parse();

        $c = 0;
        $return = array();

        foreach ($this->data AS $item)
        {
            $return[] = $item;
            $c++;

            if ($c == $num)
            {
                break;
            }
        }
        return $return;
    }

    // --------------------------------------------------------------------

    /* Return channel data for the feed */
    function & getChannelData()
    {
        $flag = false;

        if (!empty($this->channel_data))
        {
            return $this->channel_data;
        }
        else
        {
            return $flag;
        }
    }

    // --------------------------------------------------------------------

    /* Were we unable to retreive the feeds ?  */
    function errorInResponse()
    {
        return $this->feed_unavailable;
    }

    // --------------------------------------------------------------------

    /* Initialize the feed data */ 
    function clear()
    {
        $this->feed_uri     = NULL;
        $this->data         = FALSE;
        $this->channel_data = array();
        $this->cache_life   = 0;
        $this->callback     = FALSE;

        return $this;
    }
}?>