Template directory URI

Not sure why this isn’t working for me. I’m just trying to add a button to a theme using

<div class="rss"><a href="<?php bloginfo('rss_url'); ?>" title="Subscribe to <?php bloginfo('title'); ?> by RSS"><img src="<?php get_template_directory_uri(); ?>/images/footer-buttons/button-rss.png" border="0" alt="Subscribe by RSS" /> <abbr>RSS</abbr></a></div>

if I use <?php bloginfo('template_directory'); ?> instead, it works, the image won’t show using get_template_uri which is what’s recommended.