bbPress.org

Welp.. I figured it out. Here is the code that I placed in my theme’s function.php file so that all avatars are rendered correctly:

function jb_get_bp_user_avatar($avatar, $id_or_email, $size, $default, $alt)
{
    if (is_numeric($id_or_email)) {
        $id = (int) $id_or_email;
        $user = get_user_by('id', $id);
    } elseif (is_object($id_or_email)) {
        if (!empty($id_or_email->user_id)) {
            $id = (int) $id_or_email->user_id;
            $user = get_user_by('id', $id);
        }
    } else {
        $user = get_user_by('email', $id_or_email);
    }
    if ($user && is_object($user)) {
        $avatar = bp_core_fetch_avatar(array('item_id' => $user->ID));
    }
    return $avatar;
}
add_filter('get_avatar', 'jb_get_bp_user_avatar', 10000, 5);