rss

how can i put some extra code in to my RSSfeed ?
i want to ad this code in to it :

<image>
<title>Bloglog.nl</title>
<url>https://www.bloglog.nl/logo.gif</url&gt;
<link>https://www.bloglog.nl</link&gt;
<description>Nederlandse weblogs gelogd</description>
</image>

but dunno how to do it ??