Yes, this is possible:
function latest_posts_menu($items, $args) {
//To a Specific Menu
if ($args->theme_location == 'primary') {
// Parent Menu Item
$items .= '<li id="menu-item" class="menu-item">
<a href="#">' . __('Latest Posts', 'textdomain') . '</a>
<ul class="sub-menu">';
// Create Sub Menus
foreach ( get_posts(
array(
'posts_per_page'=>10,
'post_type' => array('post')
)
) as $post ) {
// Menu Thumbnail. You can change the dimenssion as well as the image class
$thumb = get_the_post_thumbnail( $post->ID, array(24,24), array("class" => "menu-thumb") );
$items .= '<li class="sub-menu-item">
'.$thumb.'
<a href="'.get_permalink( $post->ID ).'">'. $post->post_title .'</a>
</li>';
}
// Close The Menu
$items .= '</ul></li>';
}
return $items;
}
add_filter( 'wp_nav_menu_items', 'latest_posts_menu', 10, 2 );