# Pushing & Pulling — Docker Fundamentals: Images, Containers and Compose

Source: https://www.skillbyai.com/en/docker/docker-push-pull-registry

> Tag and push your images to a registry and pull them elsewhere, including private registries such as ECR.

## Namespace, tag, push

Tag your image as `<username>/<repo>:<tag>` before pushing — Docker Hub uses that prefix to know it's yours.

```bash
docker tag my-app:1.0 myusername/my-app:1.0
docker push myusername/my-app:1.0

# anywhere else:
docker pull myusername/my-app:1.0
```

## Private registries

Companies often run a private registry (ECR, GCR, ACR, self-hosted) instead of Docker Hub — the workflow is the same, just with a different registry hostname in the tag.