Eastman Kodak Co. announced that E. Mark Rajkowski has been named COO of its Digital & Applied Imaging Div. (D&AI) and that Philip Gerskovich has been appointed chief strategist of D&AI and general manager of the division's software and digital services business.   . . .    Elwood ("Woody") Spedden was named president and CEO of Photon Dynamics Inc. Spedden has been a member of the company's board of directors since April 2002.