Are you sure you are saving the photos to the SD card and not the internal memory of the camera? There should be a setting somewhere in the camera's menu to designate the default storage location. Have you formatted the SD card using the camera's menu and not on your computer? If you have formatted it on the computer, the camera may not recognize the file system and not "see" the card, and is defaulting to internal memory for storing the photos.
There is no such thing as a Nikon cp1000 or CoolPix 1000 or anything else you might be obviously referring to.
What camera do you have?
Does it support 8gb SD cards?
Are you writing to the SD card or to the buffer?