Open index.template.php
Find
// PM button
$context['menubox'][]=array(
'title' => $txt['pm_short'] . ' '. ($context['user']['unread_messages'] > 0 ? '[<strong>'. $context['user']['unread_messages'] . '</strong>]' : ''),
'link' => $scripturl.'?action=pm',
'chosen' => 'pm',
'memberonly' => true,
'guestonly' => false,
'permission' => 'allow_pm',
);
Before it add
// Gallery button
$context['menubox'][]=array(
'title' => $txt['smfgallery_menu'],
'link' => $scripturl.'?action=gallery',
'chosen' => 'gallery',
'memberonly' => false,
'guestonly' => false,
'permission' => 'allow_smfgallery_view',
);