Only Display a Featured Image on First Post Page

Question

In WordPress a single post can be divided into multiple pages using page-links.

Currently, I use featured images on my post pages and call them by size, as shown below. If an image is larger than 500 pixels it is displayed as the top-post thumbnail and if it is smaller than that it displays as the standard thumbnail.

<?php $image_data = wp_get_attachment_image_src( get_post_thumbnail_id( $post->ID ),  'full' );
if ( $image_data[1] >= 500 ) { the_post_thumbnail('top-post');
} ?>

<?php $image_data = wp_get_attachment_image_src( get_post_thumbnail_id( $post->ID ),  'full' );
if ( $image_data[1] < 500 ) { the_post_thumbnail();
} ?>

The problem is when I include this in my single-post.php it shows up on every page of a post, even when that post is divided by page-links. How do I make these images only show on the first page?

Answer 1

Use the global $page, which holds the current page number.

// Somewhere near the top
if ( $GLOBALS['page'] === 1 && $image_data = get_post_thumbnail_id() ) {
    if ( $image_data = wp_get_attachment_image_src( $image_data,  'full' ) ) {
        if ( $image_data[1] >= 500 )
            the_post_thumbnail( 'top-post' );
    }
}

// Further down. $image_data still exists, no need to grab it again.
if ( $GLOBALS['page'] === 1 && $image_data && $image_data[1] < 500 )
    the_post_thumbnail();

You'll see I also a did a little spring cleaning:

1. Removed redundant second $image_data = ...
2. Added check that there is indeed a thumbnail
3. Added check that $image_data exists