Why won't all of my pictures save to icloud?
I am having problems backing up photos from iphone 6s to icloud. (My mom's phone.) She doesn't understand technology so she hadn't backed her phone up for a year. I backed it up to icloud today before I gave her my old iphone 7. When I restored from the backup it didn't bring all of her pictures through. I went on my mac to icloud.com and sure enough, it didn't back all of them up. It only did about half of them. I backed up a second time to icloud, and they still just aren't in there. She is missing a year's worth of pictures in icloud. Both phones have all icloud photo settings turned on and both are updated to the latest software. She also has plenty of icloud storage since I made her purchase the 50gb. I don't know what else to do. PLEASE HELP! (I know several ways to transfer them to make sure they aren't lost, but I am trying to figure this out for the next time so I won't have to do this again.)
iPhone 7, iOS 11.2, null