add_filter( 'avatar_defaults', 'newgravatar' );

function newgravatar ($avatar_defaults) {
$myavatar = get_bloginfo('template_directory') . '/images/avatarimage.jpg';
$avatar_defaults[$myavatar] = "Custom Brand Name Here";
return $avatar_defaults;
}

Of course you should change the “avatarimage.jpg” to whatever you would like and the “Custom Brand Name Here” to whatever you want to show up in the Avatar section on the Discussions page.

The only thing left to do is to switch your avatar settings on the Discussions page. This will allow anyone with avatars setup at different places like Gravatar to show their own avatar…however if a user doesn’t have one, then the code above will set theirs to the default until they create their own.

Hope this helps!

Here is a screen shot from one of our clients setup, The Handmade Home. This is how it should show up on the discussions page.