title: Wordpress scales full sized image instead of serving thumbnails
body: <p>My thumbnail settings are currently: 150x150 (thumbnail), 824x824 (medium), 1024x1024 (large)</p>
  
  <p>When an archive is displayed, the thumbnails used for each post are actually the full sized image but scaled to 375x250. You'll see that if you inspect any image, thumbnails of various sizes do exist yet WP ignores them and loads the full sized image instead.</p>
  
  <p>Also, the code that loads the image is simply:</p>
  
  <pre><code>the_post_thumbnail();
  </code></pre>
  
  <p>Why is this happening? How do make it load the thumbnail instead?</p>