The big point of Docker for me is that I can build the container on my machine, run automated tests on it, play with it and then ship it to the production machi

The big point of Docker for me is that I can build the container on my machine, run automated tests on it, play with it and then ship it to the production machines when I'm confident that it is working. If you build the container on a service like this testing it is hard or in some cases even impossible. For example acceptance tests with Selenium. Gemfile.lock and similar version binding tools help, but prebuild containers bring the deployment stability to whole new level and is the reason why I'm exited about Docker and containers in general. Do they support prebuild containers?