How does one remove a Docker image?

I’m running Docker under Vagrant under OS X 10.8.4 (Mountain Lion), and whenever I try to delete a saved image, I get an error:

$ docker rmi some-image-id
2013/07/15 hh:mm:ss unexpected JSON input

According to the rmi help, the proper syntax is docker rmi IMAGE [IMAGE...], and I’m not sure what to make of that.

How can I delete an image?

$ docker version
Client version: 0.4.8
Server version: 0.4.8
Go version: go1.1

$docker info
Containers: 1
Images: 3

Interestingly, when I run docker ps, no containers show up at all. Running docker images shows four (4) base images and one (1) node image.

Try docker rmi node. That should work.

Seeing all created containers is as simple as docker ps -a.

To remove all existing containers (not images!) run docker rm $(docker ps -aq)