Hi there,
You can add the avatar like this:
add_filter( 'wpsp_author_output', function() {
return sprintf(
'<span class="wp-show-posts-byline wp-show-posts-meta">
<span class="wp-show-posts-author vcard" itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author">
<a class="url fn n" href="%1$s" title="%2$s" rel="author" itemprop="url">
%4$s <span class="author-name" itemprop="name">%3$s</span>
</a>
</span>
</span>',
esc_url( get_author_posts_url( get_the_author_meta( 'ID' ) ) ),
esc_attr( sprintf( __( 'View all posts by %s', 'wp-show-posts' ), get_the_author() ) ),
esc_html( get_the_author() ),
get_avatar( get_the_author_meta( 'ID' ) )
);
} );
Then you’ll need some CSS to style it – let me know if you need help with that.
Where on the right do you want it to show? At the bottom right corner?