Uploading photos from a Digital Camera SD Card?

I want to upload only one picture from my SD card and still keep all of the other photos on it when I put the card back into the camera. If I put the SD card in my computer, can I only take off all of the photos, or can I pick the ones I want to take, and leave the others on the SD card. Also can I put the SD card back into the camera with pictures on it? Or would I have to take all the pictures off before putting it back into the camera?

If it helps, its an SD (SanDisk) card and a Nikon camera.

Thanks!

Added (1). I borrowed the camera from a friend for a project and I only want to take off my photos and leave his. But I don't know if the camera will allow me to re-insert an SD card that has photos on it.

If you use an SD card reader rather than a cable connection to your camera it is simple.

When the SD card is inserted ignore any program that starts automatically - just shut it down.

OPen "my computer" and your SD card will appear as a drive (probably E: but could be any letter). OPen it like a standard drive and open the folder DCIM - your photos are in there. Just copy and paste the ones you want to your hard drive.

Are you sure you want to do that? SD cards are not the most reliable of media and fail quite frequently. You should get all the photos off the card onto your hard drive as a matter of routine.