Set Default Avatar

gistfile1.aw

<?php

/**
 * Set Default Avatar
 *
 * @link http://www.billerickson.net/using-gravatars-in-wordpress/
 * @author Bill Erickson
 * @param array $avatars current default avatars
 * @return array new default avatars
 *
 */
function be_default_avatar( $avatars ) {
	$new = get_stylesheet_directory_uri() . '/images/custom-gravatar.jpg';
	$avatars[$new] = "My Custom Gravatar";
	return $avatars;
}
add_filter( 'avatar_defaults', 'be_default_avatar' );