Updated Author Single.php

<?php
/**
 * The loop that displays a single post.
 *
 * The loop displays the posts and the post content.  See
 * http://codex.wordpress.org/The_Loop to understand it and
 * http://codex.wordpress.org/Template_Tags to understand
 * the tags used in it.
 *
 * This can be overridden in child themes with loop-single.php.
 *
 * @package WordPress
 * @subpackage Twenty_Ten
 * @since Twenty Ten 1.2
 */
?>

<?php
//Get the Author image by Digital Raindrops
function dr_author_image( $authorid ) {
    $slug = the_author_meta('user_nicename', $authorid );
    if ( file_exists( get_template_directory_uri() .'/images/'.$slug.'.png' ) ) {
        return get_template_directory_uri() .'/images/'.$slug.'.png); ';
    }else{
        return get_template_directory_uri() .'/images/auth-banner.png); ';
    }
}
?>

<?php if ( have_posts() ) while ( have_posts() ) : the_post(); ?>

    <?php
        //Get author image by and the author url
        $style = 'background-image: url(' .dr_author_image( $post->post_author) .');';
        $link = the_author_meta( 'user_url' );
    ?>

    <?php //display the author banner and add a link ?>
    <div class="author-banner" style="<?php echo $style; ?>" onclick="location.href='<?php echo $link; ?>'"></div>

    <div id="nav-above" class="navigation">
                    <div class="nav-previous"><?php previous_post_link( '%link', '<span class="meta-nav">' . _x( '&larr;', 'Previous post link', 'twentyten' ) . '</span> %title' ); ?></div>
                    <div class="nav-next"><?php next_post_link( '%link', '%title <span class="meta-nav">' . _x( '&rarr;', 'Next post link', 'twentyten' ) . '</span>' ); ?></div>
                </div><!-- #nav-above -->

                <div id="post-<?php the_ID(); ?>" <?php post_class(); ?>>
                    <h1 class="entry-title"><?php the_title(); ?></h1>

                    <div class="entry-meta">
                        <?php twentyten_posted_on(); ?>
                    </div><!-- .entry-meta -->

                    <div class="entry-content">
                        <?php the_content(); ?>
                        <?php wp_link_pages( array( 'before' => '<div class="page-link">' . __( 'Pages:', 'twentyten' ), 'after' => '</div>' ) ); ?>
                    </div><!-- .entry-content -->

<?php if ( get_the_author_meta( 'description' ) ) : // If a user has filled out their description, show a bio on their entries  ?>
                    <div id="entry-author-info">
                        <div id="author-avatar">
                            <?php echo get_avatar( get_the_author_meta( 'user_email' ), apply_filters( 'twentyten_author_bio_avatar_size', 60 ) ); ?>
                        </div><!-- #author-avatar -->
                        <div id="author-description">
                            <h2><?php printf( esc_attr__( 'About %s', 'twentyten' ), get_the_author() ); ?></h2>
                            <?php the_author_meta( 'description' ); ?>
                            <div id="author-link">
                                <a href="<?php echo get_author_posts_url( get_the_author_meta( 'ID' ) ); ?>">
                                    <?php printf( __( 'View all posts by %s <span class="meta-nav">&rarr;</span>', 'twentyten' ), get_the_author() ); ?>
                                </a>
                            </div><!-- #author-link -->
                        </div><!-- #author-description -->
                    </div><!-- #entry-author-info -->
<?php endif; ?>

                    <div class="entry-utility">
                        <?php twentyten_posted_in(); ?>
                        <?php edit_post_link( __( 'Edit', 'twentyten' ), '<span class="edit-link">', '</span>' ); ?>
                    </div><!-- .entry-utility -->
                </div><!-- #post-## -->

                <div id="nav-below" class="navigation">
                    <div class="nav-previous"><?php previous_post_link( '%link', '<span class="meta-nav">' . _x( '&larr;', 'Previous post link', 'twentyten' ) . '</span> %title' ); ?></div>
                    <div class="nav-next"><?php next_post_link( '%link', '%title <span class="meta-nav">' . _x( '&rarr;', 'Next post link', 'twentyten' ) . '</span>' ); ?></div>
                </div><!-- #nav-below -->

                <?php comments_template( '', true ); ?>

<?php endwhile; // end of the loop. ?>