There’s one problem with Gravatars. They are very slow to load. Each page with comments on them makes one call per comment to the Gravatar server. While a single call takes only a 100ms, on a page with hundreds of comments, we are talking about major slowdowns. Page loads can take 20 seconds and more. This plugin solves this problem by: caching gravatars with WordPress cron job.. caching gravatars on comment submission maintaining a single copy of the default gravatar instead of downloading it again and again for all the email addresses with no gravatar associtated Installation guide Support and more information