Set default avatar network-wide

I’ve seen plugins and snippets on how to set a new default avatar for a site. I’m wondering if this can be done network-wide, such that every new site on the network will have the network’s avatar as its primary default. from there the plugin’s that allow the user to upload a new avatar will be sufficient to let each site define it’s own. But until they do I’d prefer they have my avatar than the mystery man or some of the others which are downright ugly.

The avatar_default is the better option.

add_filter('pre_option_avatar_default', 'se72578_avatar_default');
function se72578_avatar_default( $option ){
   return 'http://example.com/your/default/here.jpg';
}

Simple. Stick that in a mu-plugin and you’re good to go.

Edit: If you want to still allow site owners to change the default avatar, use the default_option_avatar_default hook instead.