function plt_hide_simple_image_xml_sitemap_menus() {
//Hide the "Tools → Simple Image XML Sitemap" menu.
remove_submenu_page('tools.php', 'simple-xml-image-sitemap');
//Hide the "Settings → Simple XML Image Sitemap" menu.
remove_submenu_page('options-general.php', 'plugin_sixs');
}
add_action('admin_menu', 'plt_hide_simple_image_xml_sitemap_menus', 11);