title: Right way to delete unused docker images on OpenShift Origin
body: <p>I try to delete unused docker images on OpenShift origin. 
  What is the right way to do this?</p>
  
  <p>I tried:</p>
  
  <pre><code>docker rmi `docker images -aq`
  </code></pre>
  
  <p>This deleted all the unused images but I got something like this:</p>
  
  <pre><code>&lt;none&gt;                                           &lt;none&gt;              28e03c727eab        10 days ago         583.5 MB
  172.30.xx.xx:5000/dev-mule/mule             &lt;none&gt;              d059900ab541        4 weeks ago         985.9 MB
  172.30.xx.xx:5000/test-dev-mule/test-mule   &lt;none&gt;              d059900ab541        4 weeks ago         985.9 MB
  &lt;none&gt;                                           &lt;none&gt;              80ccbf3e9509        8 weeks ago         415.8 MB
  &lt;none&gt;                                           &lt;none&gt;              d2d658a63eb2        8 weeks ago         1.59 MB
  &lt;none&gt;                                           &lt;none&gt;              eda6efd4df85        10 weeks ago        430 MB
  &lt;none&gt;                                           &lt;none&gt;              2f0fc5db512e        10 weeks ago        711.6 MB
  </code></pre>
  
  <p>I have 7 running containers so this seems fine. The used images are still here.</p>
  
  <p>But when I perform <code>oc get images</code> I got a very big list of very much images in this style:</p>
  
  <pre><code>sha256:830ed5ad3c2deab31836b1d65877c048107d0f6788daa4a36d158386000050a2   172.30.xx.xx:5000/dev-proj/proj@sha256:830ed5ad3c2deab31836b1d65877c048107d0f6788daa4a36d158386000050a2
  </code></pre>
  
  <p>What is the right way to delete unused images in OpenShift Origin?
  I'm on version <code>oc v1.1.6</code></p>