title: Finding the layers and layer sizes for each Docker image
body: <p>For research purposes I'm trying to crawl the public Docker registry ( <a href="https://registry.hub.docker.com/">https://registry.hub.docker.com/</a> ) and find out 1) how many layers an average image has and 2) the sizes of these layers to get an idea of the distribution.</p>
  
  <p>However I studied the API and public libraries as well as the details on the github but I cant find any method to:</p>
  
  <ul>
  <li>retrieve all the public repositories/images (even if those are thousands I still need a starting list to iterate through)</li>
  <li>find all the layers of an image</li>
  <li>find the size for a layer (so not an image but for the individual layer).</li>
  </ul>
  
  <p>Can anyone help me find a way to retrieve this information?</p>
  
  <p>Thank you!</p>
  
  <p>EDIT: is anyone able to verify that searching for '*' in Docker registry is returning all the repositories and not just anything that mentions '*' anywhere? <a href="https://registry.hub.docker.com/search?q=*">https://registry.hub.docker.com/search?q=*</a></p>