photos downloading over and over

I'm not sure if I'm answering this correctly - my photos are synchronizing from my Iphone automatically through Icloud.

There are several iCloud services for photos.

• My Photo Stream: It will also download the same photos again and again after you delete it from your computer's photo library, as long as the photo is still in my Photo Stream.
• iCloud Photos: iCloud Photos can usually not create duplicates in the Photos Library on a mac by syncing, unless you are using My Photo Stream and iCloud Photos together. Are you using iCloud for Windows? I am a Mac user and cannot test this.

How are you syncing the PC with your iPhone? Are you shooting the images and videos in the High Efficiency format HEIF on the iPhone and downloading them in a more compatible format? Then the same images will download over and over again from the iPhone, unless you delete them from the iPhone.