Replace text with image in rss comment link?

I’m new to php and have been struggling for hours with this. Any suggestions greatly appreciated. I have this code:

<?php comments_rss_link(__('<abbr title="Really Simple Syndication">RSS</abbr> feed for comments on this post.')); ?>

I’m trying to use an image in it instead of the text link. Something such as this:

<img alt="RSS" src="<?php bloginfo('template_directory'); ?>/images/feed-icon-16x16.gif" style="vertical-align:-3px;" />

Thanks for any help.