title: What is the difference between the size and the virtual size of the docker images?
body: <p>I have a private registry where I store all of my docker images.</p>
  
  <p>I noticed that when I pull an image from it,the difference in the sizes of the image on my local machine and the one on the registry is significant.</p>
  
  <p>For example,I have an image called mydb (around 126 MB).</p>
  
  <p>When I pull it on my local machine and execute <strong><em>"docker images"</em></strong>, it says that the <strong>"VIRTUAL SIZE"</strong> of that image is now almost three times larger (388 MB).</p>
  
  <p>I was wondering what is the the reason for it and what <strong>"VIRTUAL SIZE"</strong> actually means.</p>
  
  <p>Thank you :) .</p>