Why isn’t my Gravatar image updating?
I changed my display pic on gravatar more than 2 days ago; but triology websites dont yet reflect.
You need to log out of Gravatar.
Gravatar doesn't seem to invalidate its cache until you are logged out. Either by doing so manually, or waiting for the session to expire (on their end).
I have actually prevented the cache from being invalidated, by continuing to visit http://gravatar.com everyday. I didn't realize at the time it was preventing the site from invalidating the cache.