由于众所周知的原因，Gavatar会拖慢网站的访问速度。可以试着用一些CDN服务来为Gavatar提速。
比如替换为V2EX的CDN：

/*use-V2EX-CDN-Gavatar*/
function getV2exAvatar($avatar) {
        $avatar = str_replace(array("www.gravatar.com/avatar","0.gravatar.com/avatar","1.gravatar.com/avatar","2.gravatar.com/avatar"),"cdn.v2ex.com/gravatar",$avatar);
        return $avatar;
}
add_filter('get_avatar', 'getV2exAvatar');