Yes. That works. Thanks!
I was also able to do it by creating an attachment.php file in my child theme, copying the single.php code and modifying it by adding:
<?php echo wp_get_attachment_image( get_the_ID(), ‘large’ ); ?>
Thanks for the quick response.
I added the code to additional CSS but it didn’t change anything in either pages or posts.
My settings for pages: Page Attributes/Template is set to “Default”. Page Layout set to “No Sidebar”.
My settings for posts: (No Page Attributes option). Page Layout set to “No Sidebar”.