From the wire colors, it's the last 4 of your 24-pins. The 20 pin and 4 pin can probably lock together. They're detachable to accomodate ATX boards that have 20 pins.
Re "bad jpg", in the fuzzy picture you're using manual focus and haven't
. Incidentally, you seem to have the camera set to restart numbering the photos when the card is removed. Many people prefer to have the camera remember numbering, so you don't end up with lots of pics having the same file name.