title: docker pull wouldn't pull latest image from remote
body: <p>I ran this:</p>
  
  <pre><code>docker pull 91xxxxx371.dkr.ecr.us-west-2.amazonaws.com/main_api
  </code></pre>
  
  <p>and nothing new was pulled, but I knew there were new images on AWS/ECR.
  So I removed the existing images:</p>
  
  <pre><code>docker rmi 91xxxxx371.dkr.ecr.us-west-2.amazonaws.com/main_api
  </code></pre>
  
  <p>and then pulled again and of course it says it retrieved new images, but that's probably just because I deleted the local tags/images or whatever.</p>
  
  <p>Why didn't the first pull command get the latest? It defaults to the latest tag.</p>