wp_get_attachment_image($post->ID, 'size-1');
The “post thumbnail” actually gets the featured image that is attached to the post. For an attachment, you want the attachment itself in a specific size, which isn’t the same as the featured image.
wp_get_attachment_image($post->ID, 'size-1');
The “post thumbnail” actually gets the featured image that is attached to the post. For an attachment, you want the attachment itself in a specific size, which isn’t the same as the featured image.