Featured image check if featured image exists and place on theme for WordPress Genesis child theme.

gistfile1.php

<?php
//* don't copy opening php tag above


//* Add featured image to top of posts
add_action('genesis_before_entry', 'featured_post_image', 8);
function featured_post_image() {
        if (has_post_thumbnail()) : ?>
                <div class="featured-image">
                        <?php the_post_thumbnail('post-image'); ?>
                </div>
        <?php endif;
}