我解决这个问题的方法是

<?php the_post_thumbnail( medium ); ?></a>"

而不是具有650 × 0的阵列。

<?php
        $args = array(
            'post_type' => 'news', // custom post type
            'orderby' => 'ID',  // order by ID
            'order' => 'DESC',   
            'posts_per_page' => -1
          
        );
        $the_query = new WP_Query($args);
        
        if( $the_query->have_posts() ) : ?>

        <?php while( $the_query->have_posts() ) : $the_query->the_post(); 
   
        $post_image_id = get_post_thumbnail_id($post_to_use->ID);

        if ($post_image_id) {$thumbnail = wp_get_attachment_image_src( $post_image_id,array(150,150));
        if($thumbnail) (string)$thumbnail = $thumbnail[0];} 
        ?>
        
        <img src="<?php echo $thumbnail;?>" >

      <?php else:  ?>
      <p>
      <?php _e( 'Sorry, no posts matched your criteria.' ); ?>
      </p>
      <?php endif; ?>

//Default WordPress

Thumbnail Sizes

The default image sizes of WordPress are “thumbnail”, “medium”, “large” and “full” (the size of the image you uploaded). These image sizes can be configured in the WordPress Administration Media panel under Settings > Media. This is how you can use these default sizes with the_post_thumbnail():


the_post_thumbnail( 'thumbnail' );     // Thumbnail (150 x 150 hard cropped)
the_post_thumbnail( 'medium' );        // Medium resolution (300 x 300 max height 300px)
the_post_thumbnail( 'medium_large' );  // Medium Large (added in WP 4.4) resolution (768 x 0 infinite height)
the_post_thumbnail( 'large' );         // Large resolution (1024 x 1024 max height 1024px)
the_post_thumbnail( 'full' );          // Full resolution (original size uploaded)
 
//With WooCommerce
the_post_thumbnail( 'shop_thumbnail' ); // Shop thumbnail (180 x 180 hard cropped)
the_post_thumbnail( 'shop_catalog' );   // Shop catalog (300 x 300 hard cropped)
the_post_thumbnail( 'shop_single' );    // Shop single (600 x 600 hard cropped)

the_post_thumbnail( array(100,100) );   // custom size add in array.

Register new image sizes for Post Thumbnails with: add_image_size().
To set the default size for Post Thumbnails see: set_post_thumbnail_size().