Can you delete photos from Photo Stream without having to transfer them to your iPhoto Library?

Can you delete photos from Photo Stream without having to transfer them to your iPhoto Library? I have hundreds that need to be deleted - when iCloud began, it transfered hundreds and hundreds of photos of weird things like symbols and country flags, that I NEVER have even seen before, let alone took a picture of. I really need to get them off my Mac Book Pro and my iPhone asap!! *****HELP HELP HELP*****😕