My Nikon D90 seems to have a trouble on how many copies of a photo it should give me. When I take a photo, I see one copy of each photos collected in my memory card as viewed through the camera. But when I plug it in my computer and view the photos, it seems like it automatically doubled up. I've reformatted my memory card and reset my camera settings but it doesn't change anything. Does my memory card/camera have a virus?