How do I backup and delete photos on my iPhone using Windows 7

Hello

My iPhone 5 is just about full and it is mostly photos and videos. I want to know how to back these up and safely delete them from my iPhone.

I currently use iCloud storage which seems to retain my photos. I know this because I had to replace a faulty phone a while ago and everything moved safely. I don't think iTunes sees all the pictures on my phone and I am not clear how to use it. I have looked in a lot of places and can't seem to find an answer to this.

My specific questions are -

1 - How do I backup the pictures on my phone using Windows 7?

2 - How do I delete them from my phone after backup?

3 - If I delete them will they still be in my iCloud backup?

4 - Can I use iTunes to do any of this? It doesn't seem to allow me to access my photos.

5 - My iCloud space exceeds the space on my phone. Is there any way I can store photos in iCloud without them being on a device?

Many Thanks,

Kevin