[yebyen]

Not really, containers are disposable and images (at least tags) are somewhat less disposable. Containers are singular, malleable units and represent a processes' running state, images are atomic and composable, inert, basically packages.

You wouldn't say that the difference between a live database and its binaries compiled source code is academic, would you?

I agree that it would make more sense if you could dump the image to a flat file with a single verb. I also think docker needs an interface to stop a pull in progress that has stalled or is no longer needed. These are academic concerns, you can submit a pull request.