/**
* Modify Featured Image Text
*/
function filter_featured_image_admin_text( $content, $post_id, $thumbnail_id ) {
$help_text = '<p><i>' . __( 'Ideal size is 800 x 471 pixels.', 'the-classicpress-theme' ) . '</i></p>';
return $help_text . $content;
}
add_filter( 'admin_post_thumbnail_html', 'filter_featured_image_admin_text', 10, 3 );
first we have this in function.php (it basically means that they replace CP default text to use the theme text that you are asking about).
in single.php, responsible to show the single blog post page we do have this:
<div id="primary">
<main id="main">
<?php
while ( have_posts() ) :
the_post();
get_template_part( 'template-parts/content', get_post_type() );
Translated it means that if there are posts they should be shown using the template in the specified directory that is template-parts>content.php
<?php
/**
* Template part for displaying posts
*
* @link https://developer.wordpress.org/themes/basics/template-hierarchy/
*
* @package Susty
*/
?>
<article id="post-<?php the_ID(); ?>" <?php post_class(); ?>>
<?php if ( is_singular() ) : ?>
<header>
<?php
the_title(
'<h1>',
'</h1>'
);
if ( 'post' === get_post_type() ) :
?>
<p class="entry-meta">
<!--span class="author-avatar">
<?php //echo get_avatar( get_the_author_meta( 'ID' ), '50' ); ?>
</span-->
<span class="post-meta">
<?php susty_wp_posted_on(); ?>
<?php susty_wp_posted_by(); ?>
<?php esc_html_e( ' | Category: ', 'the-classicpress-theme' ); ?>
<?php the_category( ', ' ); ?>
</span>
</p><!-- .entry-meta -->
<?php endif; ?>
</header>
<?php else : ?>
<header class="blog">
<?php
the_title(
'<h2><a href="' . esc_url( get_permalink() ) . '" rel="bookmark">',
'</a></h2>'
);
?>
</header>
<?php endif; ?>
<?php
if ( is_singular() ) {
susty_wp_post_thumbnail();
}
?>
<div>
<?php
the_content(
sprintf(
wp_kses(
/* translators: %s: Name of current post. Only visible to screen readers */
__( 'Continue reading<span class="screen-reader-text"> "%s"</span>', 'the-classicpress-theme' ),
array(
'span' => array(
'class' => array(),
),
)
),
get_the_title()
)
);
wp_link_pages(
array(
'before' => '<div class="page-links">' . esc_html__( 'Pages:', 'the-classicpress-theme' ),
'after' => '</div>',
)
);
?>
</div>
<footer>
</footer>
</article><!-- #post-<?php the_ID(); ?> -->
This is the code for the template part. it checks if it is a single post, and if yes the feature image is shown like a “cover” as first image under the title and meta (category, author and the like).
That is why it asks for a wide and tall one. it goes in as first image and it serves as a cover.