Eastman Kodak Co suffered a body blow on Friday when it was announced that three top executives and 10 software developers resigned from its Photo CD business to form a digital imaging unit for media mogul Mortimer Zuckerman’s Applied Graphics Technologies Inc company: the New York company plans to use the Kodak talent to develop Photo CD applications for its media and advertising customers; the mass resignation was led by Scott Brownstein, Photo CD’s chief architect, whose relationships in the computer industry enabled Kodak to form key Photo CD marketing alliances with others, including Apple Computer Inc; Kodak said that although the departed executives will be missed, there are still about 300 members on its Photo CD development team.