title: Docker commit is not saving my changes to image
body: <p>I'm new to docker world: I'm at a point where i can deploy docker containers and do some work. </p>
  
  <p>Trying to get to the next level of saving my changes and moving my containers/images to another pc/server. </p>
  
  <p>Currently, I'm using docker on windows 10, but I do have access to Ubuntu 16.04 server to test my work.</p>
  
  <p>This is where I'm stuck: I have Wordpress and MariaDB images deployed on Docker.<br>
  My WP is running perfectly OK.I have installed few themes and created few pages with images. </p>
  
  <p>At this point, I like to save my work and send it to my friend who will deploy my image and do further work on this same Wordpress.  </p>
  
  <p>What I have read online is: I should run <code>docker commit</code> command to save and create my docker image in <code>.tar</code> format and then send this image file (<code>.tar</code>) to my friend. He will run <code>docker load -i</code> on my file to load it as image into his docker and then create container from it which should give him all of my work on Wordpress.  </p>
  
  <p>Just to clarify, I'm committing both Wordpress and Mariadb containers.<br>
  I don't have any external volumes mounted so all the work is being saved in containers.</p>
  
  <p>I do remember putting check mark on drive C and D in docker settings but i don't know if that has anything to to do with volumes.  </p>
  
  <p>I don't get any error in my commit and moving <code>.tar</code> files process. Once my friend create his containers from my committed images, he gets clean Wordpress (like new installation of Wordpress starting from wp setup pages).  </p>
  
  <p>Another thing I noticed is that the image I create has the same file size as original image i pulled. When I run <code>docker images</code>, I see my image is 420MB ,as well as Wordpress image is 420MB.</p>
  
  <p>I think my image should be a little bit bigger since I have installed themes, plugins and uploaded images to Wordpress. At least it should add 3 to 5 MB more then original images. Please help. Thank you.</p>
  
  <p>Running <code>docker system df</code> gives me this.</p>
  
  <pre><code>TYPE                TOTAL               ACTIVE              SIZE                RECLAIMABLE
  Images              5                   3                   1.259GB             785.9MB (62%)
  Containers          3                   3                   58.96kB             0B (0%)
  Local Volumes       2                   2                   311.4MB             0B (0%)
  Build Cache         0                   0                   0B                  0B
  </code></pre>