Image
ELI5 — The Vibe Check
A Docker image is the blueprint or template for a container. It's like a frozen snapshot of your app and everything it needs to run. You build an image once, push it to a registry, and anyone can pull it and instantly run your app without installing anything. The image never changes — you just run containers from it.
Real Talk
A container image is a read-only, layered filesystem snapshot that contains the application code, runtime, libraries, and configuration. Images are built from Dockerfiles, tagged with versions, and stored in container registries. Each layer in an image is cached, making builds faster when only code changes.
Show Me The Code
# Tag and push an image to Docker Hub
docker build -t myuser/my-app:1.0.0 .
docker push myuser/my-app:1.0.0
# Pull and run an image
docker pull myuser/my-app:1.0.0
When You'll Hear This
"Build the image and push it to the registry so the cluster can pull it." / "Pin the image tag to a specific version — never use latest in production."
Related Terms
Container
A container is a running instance of a Docker image — it's the lunchbox you made and actually opened to eat from.
Container Registry
A Container Registry is just the specific term for a registry that stores Docker/container images.
Docker
Docker is like a lunchbox for your app.
Dockerfile
A Dockerfile is the recipe for building a Docker image.
Registry
A registry is a storage place for container images — like an app store but for Docker images. When you build an image, you push it to a registry.