It would be great to have the option to upload an image within the Edit User interface, then have the ability to display this image within a template using (something like):
the_author_image(before, after, width, height, alt)
<?php the_author_image('<p class=\"author\">', '<p>', 100, 100, 'John Smith'); ?>
This would output:
<p class=\"author\"><img alt=\"John Smith\" src=\"path/to/image.png\" width=\"100\" height=\"100\" /></p>
This could be used to display a full-size author image on an author profile page (author.php) or thumbnails for individual posts within The Loop.