Adding user pic to blog entries

If I select the "User pictures in posts" option, the pic appears perfectly within each entry on the main blog page (where the blog entries are displayed in reverse chronological order), but not on the individual post entry pages once you've clicked through.

In node.tpl.php I have the following:

<h2><?php print $picture ?><a href="<?php print $node_url ?>" title="<?php print $title ?>"><?php print $title ?></a></h2>

Do I need to call the user pic from somewhere else to make it work on the other pages? I've tried the following on page.tpl.php:

<?php if ($title): print '<h2'. ($tabs ? ' class="with-tabs"' : '') .'>'. $picture . $title .'</h2>'; endif; ?>

But this doesn't help. Any suggestions?

Thanks in advance.