How much bandwidth does this feature use? Is it only functional while on WiFi, or does it function on 3G as well? If so, this brings me back to my initial concern of how much 3G (Upload) Bandwidth does this use, per file,... I am guessing that PhotoStream uploads the Photo in it's entirety, and then downloads onto connected iCloud devices, such as an iPad or iMac... If PhotoStream does use roughly 2MB+ per Photo Upload to iCloud over 3G, wouldn't this drastically diminish a user's monthly allotment of data usage? Just curious - I appreciate all replies! Thx!