Include an option for users to select Gravatar as a profile image

[DevChive]

I would like to be able to see my profile image pulled from Gravatar so we can keep resources low and users can have universal image used.

Gravatar is linked by email address and sizes can be modified in the url params like so:

URL example:
$grav_url = "http://www.gravatar.com/avatar/" . md5( strtolower( trim( $email ) ) ) . "?d=" . urlencode( $default ) . "&s=" . $size;

Source Example:
http://en.gravatar.com/site/implement/images/php/