Stummer

<p>WordPress Plugin to add an <icon> tag with the post’s featured image to the atom feed.</p>
<h3>Features/Settings Overview</h3>
<ul>
<li>Selectable image size.</li>
</ul>
<h3>Credits</h3>
<ul>
<li>Author: <a href="https://www.stummerweb.de" rel="nofollow ugc">Henning Stummer</a></li>
</ul>


Atom Featured Image

WordPress Plugin to add an <icon> tag with the post's featured image to the atom feed.

wokamoto

<p>This plugin modifies RSS feeds and ATOM feeds as you want.</p>
<h4>How to use</h4>
<p>Putting the following templates into the current theme folder, then you can use the customized feed templates instead of the default ones.</p>
<ul>
<li>feed-atom.php – Atom Feed Template for displaying Atom Posts feed.</li>
<li>feed-atom-comments.php – Atom Feed Template for displaying Atom Comments feed.</li>
<li>feed-rdf.php – RSS 1 RDF Feed Template for displaying RSS 1 Posts feed.</li>
<li>feed-rss.php – RSS 0.92 Feed Template for displaying RSS 0.92 Posts feed.</li>
<li>feed-rss2.php – RSS2 Feed Template for displaying RSS2 Posts feed.</li>
<li>feed-rss2-comments.php – RSS2 Feed Template for displaying RSS2 Comments feed.</li>
</ul>
<p><strong>Note:</strong><br />
When these feed templates are not in the current theme folder, WordPress’s default feed templates will be used.</p>


Feed Template Customize

This plugin modifies RSS feeds and ATOM feeds as you want.

Atom Featured Image vs Feed Template Customize