Removing photos from iPhone uploaded from my MacBook

Hello,

A weekend ago I connected my iPhone to my MacBook so I could back up my iPhone. Today I noticed that every photo I have on the MacBook has been uploaded to my iPhone. I don't want these photos on my iPhone. How do I delete them without connecting, via a cable, to my MacBook? If I have to connect to my MacBook, how do I delete the photos from the iPhone without deleting them from my MacBook? And, how to I prevent this from happening in the future? Is there a setting I can check so that I never, ever, upload photos to my iPhone from my MackBook?

This has really upset me because I now have to go through the process of getting rid of these photos. I consider this feature, among other features.

Also, in future I'll connect my phone to my Windows based laptop and download them from my iPhone rather than downloading them to my MacBook.

Thanks!

[Edited by Moderator]