icloud photos on PC filling drive.
In the past, I have uploaded photos to my wife's iPad via my Windows PC (iCloud.com) in the belief these would sit on her iCloud and iPad (256GB storage iPad and pay for same on iCloud). Now I find that iCloud photos are taking up over 63GB of space on my PC's HD! Is that how it should work? At this rate I will fill my PCs hard drive. I had assumed that the PC just acted as a transfer route not as a 3rd storage location. Can anyone help, am I doing anything wrong?
Thanks