I have 200GB iCloud storage and will like to erase my pictures from my macbook, can I erase without loosing the file nor the quality?

When you say "erase my pictures from my macbook", are you saying they're resident on the MacBook itself? If that's the case, and they've all been successfully uploaded to iCloud, then yes, you can delete them from the MacBook.

No, you cannot delete the photos from any device or computer that is using iCloud Photo Library. iCloud Photo Library is a syncing service not an archival service. That means that all of those devices and computers are using the iCloud Photo Library as the source library, and any changes you make anywhere will be updated everywhere.

Think of it like Contacts. When you are signed into iCloud with Contacts turned on, then any updates you make to Contacts are uploaded to the source file for those Contacts in iCloud, and all other devices and computers signed into that iCloud account with Contacts turned on see those updates.

You can optimize the photos on the Mac, but you cannot delete them or they will be gone.

Best of luck,

GB

To optimize, go to Photos/Preferences/iCloud and set it there.