If I erase partial photos from my phone or my iPad does it erase the same photos off my iMac or the same photos in my iCloud ; all being on the same icloud account
I don’t want them erased only on iPhone and not on other devices in the same iCloud network.
yes. Any files you delete in one location are deleted everywhere. If you no longer wish to sync on a device, turn off iCloud syncing on that device.
Yes. Whatever you do on one device is reflected on all devices, that's the central purpose of using iCloud.
If I erase All of my iPhone instead of just some, does it erase all of my photos, notes, reminders, calendar, Pages etc on my iMac , iPad, and other iPhones ??
iCloud, iPhone, iPad, iMac erasures
