I use windows to store photos now. Can I upload to iCloud Drive and keep my current file integrity?

I have thousands of pictures stored on a remote drive. If I subscribe to iCloud and upload them, will it retain the file structure?

If you turn on iCloud Drive sync with your Pc or iPhone, your photos are uploaded in full quality online, while you can choose to retain on your devices a full copy or an optimized storage quality (lower quality) for storage saving purpose.