FolioVision

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:
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caching gravatars with WordPress cron job..
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caching gravatars on comment submission
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maintaining a single copy of the default gravatar instead of downloading it again and again for all the email addresses with no gravatar associtated
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<a href="http://foliovision.com/seo-tools/wordpress/plugins/fv-gravatar-cache/installation" rel="nofollow ugc">Installation guide</a>
<a href="http://foliovision.com/seo-tools/wordpress/plugins/fv-gravatar-cache" rel="nofollow ugc">Support and more information</a>

FV Gravatar Cache

I deactivated plugin but still contains elements in Database

Database Junk

Speeds up your website by making sure the gravatars are stored on your website and not loading from the gravatar server.

Marcus (aka @msykes)

Pixelite

Marcus

This is a very simple and lightweight plugin that anonymizes default avatars and prevents the user’s gravatar being automatically obtained from gravatar.com based on their registered email. This would be useful for sites where users require an extra layer of privacy, or if you just want to prevent potentially silly or embarrasing avatar accidents.
If you’re using Identicons or any other generated default avatar, the user should keep a consistent avatar unless they change their registered email.
You can also disable Gravatar completely and choose a default image to display.
This plugin is also compatible with other avatar customization plugins such as <a href="https://wordpress.org/plugins/avatar-manager/" rel="ugc">Avatar Manager</a>, <a href="https://wordpress.org/plugins/buddypress/" rel="ugc">BuddyPress</a> or <a href="https://wordpress.org/plugins/add-new-default-avatar/" rel="ugc">Add New Default Avatar</a>, since this plugin specifically prevents the gravatar of a specific user email being used and reverts to the default or user-defined avatar.
Important 3.0 Update – BuddyPress users should visit the Settings > Discussion page on your dashboard and choose one of the Disable Gravatar options to restore previous behavior.
If you have any issues or suggestions, please visit our <a href="https://wordpress.org/support/plugin/disable-user-gravatar" rel="ugc">support forums</a>.
If you find this plugin useful and would like to say thanks, please leave us a <a href="https://wordpress.org/support/view/plugin-reviews/disable-user-gravatar?filter=5" rel="ugc">5 star review</a>!

Disable User Gravatar

The plugin is a must-have for each WordPress installation. One can't process the email of the user (personal information) to create a hash and sent it to a remote server without consent of the user.

Must-have

Stops WordPress from grabbing a user avatar using their registrated email from gravatar.com.

FV Gravatar Cache vs Disable User Gravatar