New to Docker - rmi help

Hi I am new to docker ,
I have deleted an image locally using docker rmi container_id
but i also want to delete “already exists” also ?
i want to create a new image so i dont want to pull the existing one, and docker rmi is not deleting this
Please help

oot@localhost Desktop]# docker run --name bosun -d -p 4242:4242 -p 8070:8070 stackexchange/bosun
Unable to find image ‘stackexchange/bosun:latest’ locally
latest: Pulling from stackexchange/bosun
8ceedfe606fc: Already exists
a3ed95caeb02: Already exists
6e84f6881ad6: Already exists
7161d060dad4: Already exists
e827cb2043a3: Already exists
b57b71694a69: Already exists
fcb760c69b4c: Already exists
c04393ca38cc: Already exists
ccebbd1364b6: Already exists
01a3f66ea1b5: Already exists
1e4337e930e8: Already exists
4aba2babd68a: Already exists
95d3331df509: Already exists
Digest: sha256:00a859e231d90190c591fb3e8e739927d760b4e5ffff488c73950eb6bf485261
Status: Downloaded newer image for stackexchange/bosun:latest

…so just run docker build -t myname/bosun like you normally would. Docker will move the tag to your new image without disturbing the old image or any containers based on it. docker images may show the old image with just an ID and <none>; you can clean up old images on a developer system with a command like

docker rmi $(docker images -q -f dangling=true)

Why? Having those intermediate layers around isn’t harmful, and if you do docker pull the image again, it’ll save you time by not having to download them again. If you docker rmi a top-level image, it will also delete any lower-level layers that aren’t used by other images.

It is not deleting the lower level images .
i want to delete it since it is not using the network card to get the alerts of the cpu, it is using the container id to get the cpu image .

docker system prune -a -f is a new command introduced with docker 1.13. You could try this. This will delete everything on your docker which is not running. volumes, images, containers.