Product Purchase Suggestions

I would like to implement cloud imaging in an office. I have seven PCs with TI2014 installed (two 3-packs and a 1-user). Can I purchase just cloud storage and have 2014 utilize it (a la http://www.acronis.com/en-us/personal/pc-mac-backup/#cloud-storage) or would it be best to upgrade to 2015 unlimited? I do appreciate 2014's mount and try feature.

Please explain how the cloud option works. Is it the same as having a second drive for image destinations? Will it retain multiple full images and increments (daily images for x days/weeks)?

Your assistance is appreciated.

Joe