Photon to the rescue for non-square avatars. Picking up on where semantic links left off:

[code language=”php”]add_filter( ‘pre_get_avatar_data’, ‘bk_photonize_comment_avatars’, 12 );
function bk_photonize_comment_avatars( $args ) {
if ( isset( $args[‘url’] ) && ! is_null( $args[‘url’] ) && function_exists( ‘jetpack_photon_url’) ) {
$size = apply_filters( ‘genesis_comment_list_args’, array( ‘avatar_size’ => 30 ) );
$size = $size[‘avatar_size’];
$args[‘url’] = jetpack_photon_url( $args[‘url’], array( ‘resize’ => array( $size, $size ) ) ) ;
}
return $args;
}[/code]