<!-- So whenever the theme displays the post thumbnail on a page, I want it to display with this code wrapped around it... -->

<?php

	$caption = get_field( "featured_caption" );

 ?>
<div class="featured-image-wrap">
	<div class="featured-image-caption">
		<?php if( $caption ) {

    		echo $caption;

		} ?>
	</div>
	<?php if ( has_post_thumbnail() ) :
	         the_post_thumbnail();
		  endif; ?>
	</div>
</div>