icingaweb2/application/layouts/scripts/parts/navigation.phtml

<div id="menu-header"><img src="<?= $this->href('img/logo_icinga-inv.png') ?>" style="height: 2em; width:6em; float: left; margin-left: 1.5em; margin-right: 9em; margin-top: 0.5em;" alt="" /></div>
<div id="menu">
<?php


if ($this->auth()->isAuthenticated()) {
    echo $this->partial(
       'parts/menu.phtml',
        array(
            'items' => $menu->getChildren(),
            'url'   => $url
        )
    );
}
?>
</div>