After multiple support calls, I had to erase my iPhone two days ago and set it up as a new phone to fix system glitches that could not be fixed any other way. All of my photos were stored on my MacBook Pro. So I turned on iCloud photo library on the Pro and waited a day for my 18GB of photos to upload to the cloud. Then I turned iCloud photo library on on my iPhone. Nothing happened. I checked and re-checked all settings. Still no photos have downloaded to the phone. When I go to iCloud in the phone's settings under my name, a diagram shows that my 18 GB of photos are indeed stored in the cloud. However no downloading is taking place on the phone. I tried shutting down and restarting it to no avail. I am using an iPhone 6 64GB with the latest iOS software. My MacBook Pro Retina is using El Capitan, but its updates are current. After spending days trying to get iCloud photo library to work, I am very close to going back to using DropBox to get my photos from phone to laptop and vice-versa. It worked easily without any glitches. No compression with DropBox, either.