Speeds up your website by making sure the gravatars are stored on your website and not loading from the gravatar server.
Hit the "Empty Cache" button to clear the cache database and clear out the cache directory by hand (you can see the path at the very top of the Settings screen). Then hit the "Run Cron Now" button, it will refresh a couple of gravatars, so you can check the cache directory again, to see if it's filling up correctly. "Current Cron offset:" will increment, so you can track the progess and see how the cron is running. You can also turn on "Debug mode" and check log.txt afterwards.
These types of gravatars are not currently supported. Drop us a note and we might add this feature in next release.
You can turn edit your template to turn off the FV Gravatar Cache just when needed, add this code right before that section in your WordPress template php file:
<?php global $FV_Gravatar_Cache; remove_filter( 'get_avatar', array( &$FV_Gravatar_Cache, 'GetAvatar' ) ); ?>
In case you need the FV Gravatar Cache running later in the template, just bring it back with:
<?php global $FV_Gravatar_Cache; add_filter( 'get_avatar', array( &$FV_Gravatar_Cache, 'GetAvatar' ) ); ?>
If you selected empty gravatar in wp-admin -> Settings -> Discussion, then it's ok. Otherwise try to resave the options and it should appear.