Logo above header

I created a theme in artisteer and added a logo above the header inside the header.php with the following line above where the header is:

<img src="<?php echo bloginfo('stylesheet_directory');?>/images/template/logo.gif" alt="<?php bloginfo( 'name' ); ?>" width="174" height="52"/>

With doing that, some of my header went down behind the content. What happened? Thank you