Arg I set the size in the wrong spot... lol
Now I got it!
ETA: there are two ways to fix it, both have their pros and cons.
One is to change the css to:
max-width: 1.5em !important;
max-height: 1.5em !important;
the other is to change in Subs.php:
'title' => (!empty($user_info['avatar']['image']) ? $user_info['avatar']['image'] . ' ' : '') . (!empty($modSettings['displayMemberNames']) ? $user_info['name'] : $txt['account_short']),
to:
'title' => (!empty($user_info['avatar']['url']) ? '<img class="avatar" src="' . $user_info['avatar']['url'] . '" alt="" /> ' : '') . (!empty($modSettings['displayMemberNames']) ? $user_info['name'] : $txt['account_short']),
Both work, let's just pick one for now. In the next version it would be nice to throw out some stuff and use css for everything. (Or as much as possible. )