How do I stop my iPhone 6s from sending every photo that I take to iCloud? Can it be set to send manually only the photos that I want to keep?

I use my phone a lot in my workplace, too enlarge small labels, for temporary info gathering etc. My phone then clouds my iCloud space with all these temporary stuff that I have no intention of keeping for more than a day or two. Then it proceeds to "push" all that stuff to my laptop at home and my iPad. I only want to keep a perhaps 5 or 6 out of a 100 photos. Is there a way to keep this automatic process from taking place/ Or am I stuck with buying more iCloud space?