Using Photos in Windows 10 to download iPhone photos.

Every time I connect my iPhone (5s on iOS 9.0.2) to my Windows 10 computer (HP Pavilion dm4) it thinks all my photos are "new" and imports them all.  Or does it?  There don't seem to be duplicate files on the computer, but it does seem to go through the process of importing them all, at least so far as the progress bar shows and the time that it takes and the number of photos it claims to be importing.  Any way to have it only recognize and process the genuinely _new_ photos since the last download/connection?