> Docker is a read-only template with instructions for creating a Docker container..
> An image may be an independent or may be based on other image with some customization.
> It is a file which is used to execute the code in Docker container.
>The docker image runs only in the docker platform.
>A Docker image contains application code, libraries, tools, dependencies and other files needed to make an application run
>It might be a group of files or filesystem or an environment to run an application.
>A common environment can be created as an image to run multiple applications too.
> Docker uses images to improve the quality of the application, to reduce the size of the application and to utilize the memory efficiently.