Q: iCloud

iCloud is not a storage device - it is more to sync your images across devices

iCloud Drive FAQ - https://support.apple.com/en-us/HT201104

Jan. 2016: Using iCloud Drive without caching files locally on computer - https://discussions.apple.com/message/29707288#29707288 - "You can turn off iCloud Drive on your Mac (system preferences > iCloud > iCloud drive > off) and access iCloud Drive via your browser at iCloud.com > iCloud Drive."

Rationale behind iCloud storage - Jan 2016 - https://discussions.apple.com/message/29713224#29713224

From a post by Limnos

Yes - several options really

1. Import them to your computer

Import photos and videos from your iPhone, iPad, or iPod touch to your computer - Apple Support

2. You can offload your computer to an external hard drive

3. You can use a cloud service like Carbonite, Google Drive or OneDrive to store the images

Any other questions please feel free to ask

To increase space available, go Settings/iCloud/Photos and select Optimize iPhone/iPad Storage. That will reduce the space required by about 90% when fully effective.