add_filter( 'avatar_defaults', 'newgravatar' );

function newgravatar ($avatar_defaults) {
$myavatar = get_bloginfo('template_directory') . '/images/gravatar.gif';
$avatar_defaults[$myavatar] = "WPBeginner";
return $avatar_defaults;
}

http://www.wpbeginner.com/wp-tutorials/25-extremely-useful-tricks-for-the-wordpress-functions-file/

Code in functions.php einfügen

Standard Gravatar in Wordpress ändern

wordpress

PHP