Q: How can I save my photos from iCloud to my PC?

The fastest and easiest way would be to import them directly from your phone to the computer: Import photos and videos from your iPhone, iPad, or iPod touch to your computer - Apple Support

That is if the full size originals are still on the phone. If not you can download them from https://www.icloud.com/ by going to Moments in the Photo app there and click Select Photos in the bar at the top, select the ones you want to download and then click the download icon.

Sorry -- when you mentioned photos on iCloud I assumed iCloud Photo Library. Only iCloud Photo Library photos are accessible on iCloud.com.

Note that Photo Stream photos do not count toward your iCloud storage, although if you are backing up to iCloud the original camera roll photo is included in the backup and that does count: My Photo Stream FAQ - Apple Support

That same link has some ways of accessing your Photo Stream from a windows pc, although as stated in my original post the simplest way ay be to simply import them directly from your phone via the USB cable.

The following has some other ideas about ways to reduce your iCloud storage: Manage your iCloud storage - Apple Support