Try to disable iCloud picture management on any iOS device you want to manage manually (or use a third-party photo management application). You don’t have to completely disable iCloud (you can continue to use iCloud for your contacts, calendar, and other functions), but you do have to disable all the photo backup and sharing options.
To disable iCloud photo management on your iOS device navigate to Settings > iCloud > Photos, and then uncheck the “iCloud Photo Library” option.
Once you’ve toggled the above settings, you’re free to connect your device to your computer, and then manually manage your photos. No iOS device restart necessary—the change in permissions takes place immediately after your change the settings.