There are a couple things you can try if the author avatar isn't displaying.
- Check the first parameter. WordPress deprecated get_the_author_id()
a while ago, so depending on your version of WordPress, they may have removed this function.
Try replacing it with: get_the_author_meta('user_email') - You might be trying to display the avatar at a larger size than the original. Get the size of the image directly from your users page (
/wp-admin/users.php), then try displaying the avatar at that size.
For example, if your avatar is only 32 pixels wide/high, try the following:
<?php echo get_avatar( get_the_author_meta( 'user_email' ),
apply_filters( 'twentyten_author_bio_avatar_size', 32 ) ); ?>