src/Ease/User.php
public static function getGravatar(
        $email, $size = 80, $default = 'mm', $maxRating = 'g'
    )
    {
        $url = 'http://www.gravatar.com/avatar/';
        $url .= md5(strtolower(trim($email)));
        $url .= "?s=$size&d=$default&r=$maxRating";

        return $url;
    }
public static function getGravatar(
        $email, $size = 80, $default = 'mm', $maxRating = 'g'
    )
    {
        $url = 'http://www.gravatar.com/avatar/';
        $url .= md5(strtolower(trim($email)));
        $url .= "?s=$size&d=$default&r=$maxRating";

        return $url;
    }
Get either a Gravatar URL or complete image tag for a specified email
address.

@param string $email     The email address
@param integer $size      Size in pixels, defaults to 80px [ 1 - 512 ]
@param string $default   [ 404 | mm | identicon | monsterid | wavatar ]
@param string $maxRating Maximum rating (inclusive) [ g | pg | r | x ]

@return string containing either just a URL or a complete image tag

@source http://gravatar.com/site/implement/images/php/