By assuming realistically that the photon is an ultrarelativistic particle of non-zero rest-mass, we determine this mass as a function of wavelength at the geometric-optics limit. In fact, we find that the photon rest-mass at the above limit is almost proportional to wavelength. In addition, we calculate the photon kinetic energy and momentum as functions of wavelength at the geometric-optics limit. ©2017 Old City Publishing, Inc.