Hey, this is my first post, and I'd like to start with a small "mod" ... this one shows vldpersonals avatars in phpBB3.
I modified some things in mod.phpbb3.php:

In function mod_phpbb3_add_member(), change

    $result = $DB->query("SELECT username, password, email, lastvisit, joindate, ipaddress, picture, picture_active FROM  " . DB_PREFIX . "members WHERE member_id='" . $params['member_id'] . "' LIMIT 1");

add

    if ($user_data['picture_active']) {
        $user_avatar = mod_phpbb3_get_avatar($user_data['joindate'], mysql_real_escape_string($user_data['picture']), $params['member_id']);
        $user_avatar_type = "2";
    } else {
        $user_avatar = '';
        $user_avatar_type = "0";
    }

change

    $where_sql = "SET group_id=2,
        username = '" . $user_data['username'] . "',
        username_clean = '" . strtolower($user_data['username']) . "',
        user_password = '{$user_data['password']}',
        user_passchg = '{$user_data['lastvisit']}',
        user_email = '{$user_data['email']}',
        user_type = {$user_data['inactive']},
        user_inactive_reason = {$user_data['inactive']},
        user_regdate = '{$user_data['joindate']}',
        user_lastmark = '{$user_data['lastvisit']}',
        user_avatar = '{$user_avatar}',
        user_avatar_type = '{$user_avatar_type}',
        user_avatar_width = '100',
        user_avatar_height = '100',
        user_lastvisit = '{$user_data['lastvisit']}'";

Also add a new function:

function mod_phpbb3_get_avatar($joindate, $image, $id)
{
    $media = substr($joindate, -1, 1).'/'.
    substr($joindate, -2, 1).'/'.
    substr($joindate, -3, 1).'/'.
    substr($joindate, -4, 1).'/'.
    $id.'/'; 
    return '/v2/media/uploads/'.$media.'t_photo_'.$image;
}

That's it. Adapt to your path, and you should be ready to go. (Of course, external avatars have to be activated in phpbb3.) What do you think?