title: How to check what's inside of a docker image?
body: <p>Searching for a best-fit image for a project, you traverse the Docker's Hub and encounter many images. Depending on what they offer, you can choose between <code>slim</code>, <code>alpine</code>, <code>buster</code>, versioned images, <code>latest</code> image, etc.</p>
  <p>How to see what's inside an image (what kind of layers are there)? Is it possible to list libraries and drivers contained in an image? How can I ensure my Redis image has proper drivers and libraries to work with Django? How to see if an image utilizes <code>apt</code>, <code>apt-get</code>, <code>apk</code> for package management, or if it doesn't provide such utility at all?</p>
  <p>Also, I'd like to check it before fetching an image from Hub, if possible. Launching <code>docker run -it [...]</code> is a way to make such checks, but not very efficient if we have to download &gt;1GB image beforehand.</p>