Docker Images vs Containers: Key Differences Every Beginner Should Know

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Docker images and containers are related but distinct concepts that often confuse newcomers to the platform. An image is a read-only template stored once on disk, while a container is a live, running instance created from that image — similar to a class and an object in programming. Multiple containers can be launched from a single image simultaneously without duplicating files on disk, making Docker storage-efficient. Each container gets its own thin writable layer on top of the shared image, meaning changes in one container do not affect others. However, this writable layer is temporary and is deleted when the container is removed, so persistent data requires the use of Docker volumes.

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