Echo list attachment size in post

wp_get_attachment_thumb_url() doesn’t accept three parameters. It takes one– the attachment ID. And, as you might guess from the name of the function, it return the thumbnail URL *_thumb_url. If you’d have simply checked the Codex entry for the function you’d have seen that.

If you’d check the Codex, you’d see several other things too

1. Don’t use query_posts()

   Note: This function isn’t meant to be used by plugins or themes.

2. numberposts has long since been deprecated. In fact, it may not
   work at all anymore as I can’t find it mentioned in the Codex any
   longer, nor do I see it the source for WP_Query.

Let’s correct this. The key function you want is wp_get_attachment_image_src(), but your code is an poorly formatted, unreadable mess. Let’s fix that too.

1. Use a new WP_Query object instead of query_posts() I don’t know
   what arguments you are using as you didn’t post that part.
2. Use posts_per_page instead of numberposts (which name never made
   sense anyway)
3. Use wp_get_attachment_image_src()
4. Indent, and format, and organize. Save your sanity man!

Which gives us…

$args = array('post_type' => 'post'); // not sure what your actually are.
$images = new WP_Query($args);

if ($images->have_posts()) { 
  while ($images->have_posts()) { 
    $images->the_post();
    $args = array( 
      'post_type' => 'attachment', 
      'posts_per_page' => 3, 
      'orderby' => 'rand', 
      'order' => 'DESC', 
      'post_mime_type' => 'image' ,
      'post_status' => null, 
      'post_parent' => $post->ID 
    ); 
    $attachments = get_posts($args);
    if ($attachments) {
      foreach ( $attachments as $attachment ) { 
        $image = wp_get_attachment_image_src( $attachment->ID,'large', false ); 
        if (empty($image[0])) continue;
        $image_meta = get_post_meta($attachment->ID, '_wp_attachment_image_alt', true); ?>
        <a href="https://wordpress.stackexchange.com/questions/207756/<?php echo $image[0]; ?>" title="<?php the_title(); ?>">
          <img src="https://wordpress.stackexchange.com/questions/207756/<?php echo $image[0]; ?>" alt="<?php echo $image_meta ?>" />
        </a><?php
      }
    }
  }
} 
wp_reset_postdata();