Help With Displaying Avatar of Commenter

Hi there,

I presume this line of code in the comment loop inserts the avatar of user id ‘1’ next to every comment, whether or not it was posted by user ‘1’?

<?php echo get_avatar(1,'32','identicon'); ?>

How should this be modified to retrieve the ID (and avatar) of the user actually posting the comment?

i.e. in the spirit of:

<?php echo get_blog_avatar($wpdb->blogid,'128','identicon'); ?>

Thanks!