the featured image should by default appear in the posts list, however, it would be full width above the content…
do you have a featured image set for each of the three top posts?
please post a link to your site to illustrate your problem.
correction:
the featured image does not appear by default;
to have the featured image in the front page blog section, you might need to edit /template-parts/post/content-excerpt.php in a child theme, and add this:
<?php if ( '' !== get_the_post_thumbnail() && is_front_page() && get_option( 'page_on_front' ) ) : ?>
<div class="post-thumbnail">
<a href="<?php the_permalink(); ?>">
<?php the_post_thumbnail( 'twentyseventeen-featured-image' ); ?>
</a>
</div><!-- .post-thumbnail -->
<?php endif; ?>
between the code of the title and the entry summary.
you might need CSS to align the image.
Thanks so much for this!
I’ve been messing about with the content-front-page-panels.php file for ages trying to solve this on the TwentySeventeen theme, until I found your content-excerpt.php suggestion.
Saved me lots of headaches!!