How can I generate local docker image

I’m using the plugins/docker plugin but when I run drone exec --local I want to generate the docker image locally. I’ve tried various settings with plugins/docker, like specifying a repo like local/my-image and removing the registry setting. All of these attempts generate an error when run:

0dc1ec77adb3: Waiting
c2dca236d8e6: Waiting
denied: requested access to the resource is denied
time="2017-10-16T16:12:43Z" level=fatal msg="exit status 1"
2017/10/16 17:12:45 drone_step_2 : exit code 1