Hi there,
You can't use any form of imaging in conjunction with the Symantec.cloud service. Essentially each license you have is linked to the machines SID. If you then clone that machine, you will end up having multiple instances of that same agent essentially. These additional agents will not be able to update from the portal, and may have trouble getting Virus updates. This was put in place, I believe, to avoid people paying for just one license and getting potentially hundreds of machines protected.
Hope this helps.
Regards,
- FP