Gravatar Privacy Proxy
Gravatar Privacy Proxy protects your visitors' privacy on your Wordpress site. Instead of Gravatars being requested from gravatar.com directly, Gravatars will be loaded from an internal, caching PHP proxy script.
Download one of the recent releases from GitHub as a ZIP file. In Wordpress select "Plugins > Add new > Upload Plugin" and select the downloaded file. Activate the plugin after installation.
You need to have the PHP curl extension enabled. No additional configuration is required. Make sure that your PHP-user is able to create new directories and files in the plugin directory.
Works with Wordpress 4.4.2 or newer.