Is this a third nipple? Can it be removed? (Photo)

Dear jo3000,
It is hard to tell for sure without an examination. If you are considering a surgery, I would suggest you to consult a board-certified plastic surgeon. Only after a thorough examination you will get more information and recommendations.
Daniel Barrett, MD
Certified, American Board of Plastic Surgery
Member, American Society of Plastic Surgery
Member, American Society of Aesthetic Plastic Surgery

There is a medical term for extra nipples, "supernumerary nipples", because the condition is actually fairly common.  Your board certified plastic surgeon can do an examination of the area and determine if that is the likely cause of the pigmented area on the upper breast.  If there is any suspicion of another pigmented skin tumor, your doctor would make recommendations, but if not, then they can discuss options for removal.  The assessment should be done in person rather than from a photo.  The removal would typically be done under local anesthesia and result in a small scar.  (Incidentally, there are some instances of extra nipples being associated with extra breast tissue, an accessory breast).