How to select featured images for 1500 posts?

Question

I have over 1500 posts I imported from Tumblr. While the images were imported into the gallery, I need to make sure there's a featured image for each. How do I make the images (12 per post minus 30 that don't have images) a featured image automatically?

Answer 1

You can run a script that will programmatically set the featured image for each post. You can use the first attached image for this. To get the attached images run a query for the posts and loop through each one and use get_children() setting the post_parent to the current post id in your loop.

$posts = get_posts( array( 'posts_per_page' => -1 ));

foreach ( $posts as $post ) {

   $featured = wpse_get_attachments( $post->ID );
   foreach( $featured as $attachment ) {
     $img = set_post_thumbnail( $post->ID, $attachment['ID'] );
   }
   if ( $img )
       echo 'Featured image set for '. $post->ID; 
}
/**
 * Queries for attached images and returns first.
 *
 * @param int $post_id The post id to check if attachments exist
 * @return array|bool The 1st attached on success false if no attachments
 */
function wpse_get_attachments( $post_id ) {
    return get_children( array(
            'post_parent'    => $post_id,
            'post_type'      => 'attachment',
            'post_mime_type' => 'image',
            'posts_per_page' => (int)1
        ), ARRAY_A
    );
}

You would need to put this code somewhere it can get executed like a custom page template that you would load only one time to set the featured images.

You could also use a plugin I wrote that will do this via an admin tools page via ajax. http://wordpress.org/extend/plugins/media-tools/