What is the difference between an image and a container?

Image — a static, immutable template containing everything needed to run an application: code, libraries, dependencies, environment variables, and configuration files. An image is created based on a Dockerfile.

Container — an executable, isolated instance of an image. It is a running process with its own filesystem, network, and processes based on the image. Containers can be started, stopped, removed, and moved between systems.

Main differences:

Characteristic	Image	Container
Type	Static template	Executable instance
State	Immutable	Mutable (process state)
Lifecycle	Created from Dockerfile, can be deleted	Started from an image, stopped, deleted
Filesystem	Layered, immutable	Layer for writing on top of image layers
Resources	None	Uses host machine resources (CPU, RAM, network)