How do I remove all my photos from my MacBook Air to free up space but keep them all on my phone

Hi, you can transfer them to iCloud and optimize your mac storage. This way only smaller version of your photos will be saved on your mac and full hd will be backed up on your icloud and can he viewed from any of your devices.

1. Make sure your Mac is connected to a Wi-Fi network
2. Launch the Photos application and click on Photos in the top left corner
3. Click on Preferences…
4. Click on the iCloud tab
5. Click on the check box next to iCloud Photo Library
6. Do not click on Download Originals to this Mac, instead select Optimize Mac Storage.