Thumbnails not showing up in my posts

Hello,

I have a problem. Thumbnails are not showing up in my posts.

Here is my website: https://www.parttimedaddy.com

Here is a template demo:
https://convergence.themedemo.net/

I have uploaded an image and connected it to the specific post, even posted it inside the post, but the front page is not picking it up.

Some templates give me an option to “set this image as a feature image” which also assigns the thumbnail, but i dont have that option in this case.

Index.php has the following code:
<div class=”content”>
<?php $postimageurl = get_post_meta($post->ID, ‘post-img’, true); if ($postimageurl) { ?>
<div class=”pic fl”>
” rel=”bookmark” title=”Permanent Link to <?php the_title_attribute(); ?>”><img src=”<?php echo $postimageurl; ?>” alt=”Post Pic” width=”200″ height=”200″ />
</div>
<?php } ?>