Fredymac wrote: "What I meant to say was that I was trying to save space on my iPad by moving the photos that reside on my iPad to iCloud.
Right. iCloud doesn't work that way. iCloud Photos isn't a storage service. iCloud is a synchronization service. iCloud is designed to make all the pictures available on all the connected devices. When you engage iCloud Photos, for instance, then the Library on that device is kept exactly the same as the iCloud Photos Library. So, for instance, if you take a picture with your iPhone, it is added to the iPhone's Photos Library, copied to iCloud Photos Library at iCloud.com, and then copied to the Photos Library on each of the other devices that you have connected. If you delete a picture on your Mac, then that picture is deleted at iCloud and on all the other devices. So you can't think of iCloud Photos as a full backup service, since it backs up mistakes. And it isn't separate storage, because whatever is at iCloud.com is also on your iPad, iPhone, and Mac. They are all kept the same.
With iCloud, you can use Optimize Storage on a Mac, on your iPhone, or on your iPad. If you set a device to "Optimize Storage,"on your iPad, then Photos may store only smaller images on the iPad and rely on iCloud to keep the full sized images. This is great, since with the lower resolution images you can scan through pictures very quickly, and they look great on the screen. So, if Optimize is chosen, and you want to edit a picture, Photos will reach out to iCloud to get a full sized image for you to work on. It's the same for printing or anything that demands the full picture. Your optimized Library may take up less than 20% of the space of a fully downloaded Library.
So if your objective is to free up space, then you must turn on iCloud Photos, and you must turn on Optimize Storage in the iCloud Photos settings.
