title to logo jpeg

I searched and read about how to change the title to a picture (jpeg) however, it says to open header.php in my theme (twenty ten) and If the site in question is the one linked to in your profile open header.php search for:

<div class=”logo”>“><?php bloginfo(‘name’); ?></div>

Replace with:

<div class=”logo”>“><img src=”<?php bloginfo(‘template_directory’); ?>/images/logo.gif” /></div>

BUT, I do not see this in header.php (used find function)? Help please?