Recently I start using Gravatar (an abbreviation for globally recognized avatar). It is a free service for providing globally-unique avatars which was created by Tom Werner for blogs and web forums. I want to embedded it in my WordPress 2.7 template. So I try to insert the additional code as below in comments.php and it works. I set my icon size to 50x50. Others might like 40x40. It's depend on personal preference.
<?php if(function_exists('get_avatar')) { echo get_avatar($comment, '50'); } ?>
Original comments.php
<li <?php echo $oddcomment; ?>id="comment-<?php comment_ID() ?>"> <cite><?php comment_author_link() ?></cite> Says: <?php if ($comment->comment_approved == '0') : ?> <em>Your comment is awaiting moderation.</em> <?php endif; ?> <br />
New comments.php
<li <?php echo $oddcomment; ?>id="comment-<?php comment_ID() ?>"> <?php if(function_exists('get_avatar')) { echo get_avatar($comment, '50'); } ?> <cite><?php comment_author_link() ?></cite> Says: <?php if ($comment->comment_approved == '0') : ?> <em>Your comment is awaiting moderation.</em> <?php endif; ?> <br />