Media RSS continues to get consumed in more and more places, from sites like FriendFeed to embeddable widgets like this slide show based on the Google AJAX Feed API.

So I thought I'd use it to add thumbnails to my site's Atom feed. It turned out to be surprisingly easy -- I just had to include a <media:thumbnail> element in each <entry> with an associated image.

For example, this post will appear something like this in the feed:

<entry>
 <id>http://www.tomstocky.com/blog/adding-mediarss-to-atom</id>
 <published>2008-12-04T10:15:00-08:00</published>
 <updated>2008-12-04T10:15:00-08:00</updated>
 <title>Adding Media RSS thumbnails to an Atom feed</title>
 <link href="http://www.tomstocky.com/blog/adding-mediarss-to-atom"
   rel="alternate" type="text/html" />
 <content type="xhtml" xml:base="http://www.tomstocky.com/">
  <div xmlns="http://www.w3.org/1999/xhtml">
   ... content ...
  </div>
 </content>
 <media:thumbnail xmlns:media="http://search.yahoo.com/mrss/"
   url="http://www.tomstocky.com/img/t/adding-mediarss-to-atom.gif"
   height="150" width="300" />
</entry>

One thing I wasn't able to track down were the size constraints for these thumbnails. I assume that consumers of Media RSS have maximum widths and heights in mind for these images, but I couldn't find anything definitive. Let me know if you happen to be aware of a max thumbnail size ...