Undoing Images from Site Servers

Good morning everyone.  I have a question and would like insight on how this works.  I understand when creating an image using DS7.x that by default all images will be replicated to all Site Servers.  Going into Settings->Deployment and Migration-> Disk Images and then clicking on the Package Server tab allows you to control which servers that image will replicate to.

My question is once the images have already replicate how do you undo this action?  Can you simply pick (or un-pick) the server you want to have the image and will this delete them from the other site servers?  Or do you have to set this and then manually delete the images from the servers that do not need to keep a copy any longer.

Thanks