Deleting photos across devices

I take photos from my iPhone and I like to use photo stream to automatically upload them to iPhoto and my iPad. But, I delete a lot of the photos. Maybe I took 5 of one shot and only one was good. Or maybe I took one of a receipt and now that I've saved it I don't need it anymore.

But now I have these photos that I want to delete saved on my mac and my iPad. Why don't they delete everywhere? Can I fix this?