Storage is full

So I just learned that iPhone storage and iCloud storage are different. My iPhone’s storage is too full to download the next upgrade. First, I bought more iCloud storage thinking it would resolve this issue. Then tried to delete some apps I was not using and they would not delete. I deleted pictures that were in messages and attachments but still don’t have enough storage.

The big question, I don’t need all the pictures I have (many of them) but would like to keep my pictures in the iCloud since I have a lot of storage there. When I try to delete a picture, it says it will be deleted out of iCloud too. Is there a way to keep pictures in the iCloud but delete them from the iPhone? And will it help to resolve my storage issues?

Thank you for your help.