This option edits the image to tell the operating system to copy the image to a swap file and run it from there. Use this option for images that reside on networks or removable media.
You can add or remove the NET or CD qualifiers:
NET indicates that the image resides on a network.
CD indicates that the image resides on a CD-ROM or similar removable medium.
Use !NET and !CD to reverse the effects of NET and CD.