Cookies from Static Content

define('COOKIE_DOMAIN', 'www.mydomain.com');

Is that the right thing to put into the wp-config file?

Or as i have images coming out of a subdomain I should put:

define('COOKIE_DOMAIN', 'www.images.mydomain.com');

or should it be:

define('COOKIE_DOMAIN', 'www.mydomain.com', 'www.images.mydomain.com');