Template tag help

Hi, I’m using the following code within the single.php template page.

My issue is I can’t use the template tag within the echo statement, is there a way around this so that the template tag works instead of hard coding the url cheers.

<?
if (in_category('3203')) { echo('
<div>
<img src="<?php bloginfo('template_url'); ?>/images/banner1.jpg" />
</div>
'); }
elseif (in_category('3204')) {
echo('
<div>
<img src="<?php bloginfo('template_url'); ?>/images/banner2.jpg" />
</div>
'); }
elseif (in_category('3205')) { echo('
<div>
<img src="<?php bloginfo('template_url'); ?>/images/banner3.jpg" />
</div>
'); }
?>

Any help welcome, cheers