Please cache gravatar images locally

Georg Ringer reported an issue

To improve privacy and performance please cache the gravatar images locally

Reported URL:https://my.typo3.org/index.php?id=23&tx_t3oslack_pi1%5Baction%5D=connect&tx_t3oslack_pi1%5Bcontroller%5D=SlackUser&cHash=c4143ce98ba6f5694e30ce6c15f1ce8a

User Agent:Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/67.0.3396.87 Safari/537.36