Where and how does the process of uploading a Docker image to the repository occur?

The process of uploading a Docker image to a repository (push) occurs on the client side using the docker push command.

1. First, a Docker image with a specific tag is built locally or already exists.
2. Then, the command is executed:

docker push <repository>/<image_name>:<tag>

3. The Docker client connects to the remote Docker Registry (repository) and authenticates if required.
4. The image is broken into layers, and each layer is uploaded to the repository sequentially.
5. After all layers are successfully uploaded, the repository updates its metadata to make the image available for download.

Thus, the upload occurs on the client side, and the repository receives and stores the image layers.