function plt_hide_optimus_menus() {
//Hide the "Tools → Optimize all images" menu.
remove_submenu_page('tools.php', 'optimus-bulk-optimizer');
//Hide the "Settings → Optimus" menu.
remove_submenu_page('options-general.php', 'optimus');
}
add_action('admin_menu', 'plt_hide_optimus_menus', 11);