Featured Image Theme Wordpress

Kok featured imagenya tidak keluar, ya?

Isi functions.php

 <?php

function load_files(){
	wp_enqueue_style('style', get_stylesheet_uri() );
}

add_action('wp_enqueue_scripts','load_files');

//---excerpt

function get_excerpt_text(){
	return ' ';
}
add_filter('excerpt_more','get_excerpt_text');

function init_setup(){
	//--menu
	register_nav_menus(array(
		'main_menu' => 'Menu Utama',
		'footer_menu' => 'Menu Footer'
	));
	//--featured image
	add_theme_support('post-thumbnails');
}

add_action('after_setup_theme','init_setup');

?>

Index.php

 <?php get_header(); ?>
<main>
<?php
if( have_posts() ):
	while( have_posts() ):
		the_post();
		get_template_part('content');
	endwhile;
else:
echo "Tidak ada postingan";
endif;
?>
</main>
<?php get_footer(); ?>

content.php

 <?php if(is_single()){ ?>
	<h3><a href="<?php the_permalink(); ?>"><?php the_title();?></a></h3>
	<p class="meta-info">
		Posted  <?php the_date('F j, Y'); ?> at <?php the_time('g:i a'); ?> by <a href="<?php echo get_author_posts_url(get_the_author_meta('ID'));?>"> <?php the_author(); ?> </a> on <?php the_category(', ');?>
	</p>
	<p><?php echo the_content();?></p>
<?php
}
else{
?>
	<h3><a href="<?php the_permalink(); ?>"><?php the_title();?></a></h3>
	<p><?php echo get_the_excerpt();?><a href="<?php the_permalink();?>">Read More...</a></p>
	<p class="meta-info">
		Posted  <?php the_date('F j, Y'); ?> at <?php the_time('g:i a'); ?> by <a href="<?php echo get_author_posts_url(get_the_author_meta('ID'));?>"> <?php the_author(); ?> </a> on <?php the_category(', ');?>
	</p>

<?php
the_post_thumbnail();
} ?>