Adjust the settings so only thumbnails of photos are stored on the phone while the original images are in the cloud.
ON THE IPHONE:
- Launch Settings, tap on the Photo option.
- Turn on the virtual switch for iCloud Photos.
- Tap on the Optimize iPhone Storage option.
ON MOST ANDROID DEVICES:
Launch the Camera App, then tap on the Settings icon
Turn on the virtual switches for High efficiency pictures and High efficiency videos.