icloud storage

No. Do not do that. iCloud is more of a synching service rather than an archival service. If you delete the photos on your iPhone then those will be deleted from iCloud and all the devices that those photos are synched to..

What you can do is Open Settings ➔ Photos ➔ Optimize iPhone Storage : Set this to ON.

This will store low resolution photos on your iPhone and the original resolution photos on iCloud. You will not have to delete anything and the space, that these photos, occupy will be freed up for use on the iPhone.

Here is more information on ➔ What is iCloud Storage? - Apple Support.

Axel F.

if you are using iCloud Photos and you delete pictures from your iPhone, they will also be deleted from iCloud