Upload How Can I Upload Pics From My Camera To Computer Without Duplicating Old Ones?

How can I upload pics from my camera to computer without duplicating old ones? - upload

My computer is supposed to collect only, this is already done, but you want to start, and then copy that I downloaded are. I will not delete old files on the memory card from my camera, but I do not want a few copies on my computer. I want to make only the most recent photos. I use Windows Media Gallery. Thank you!