Problems associated with the use of the process e++e--->2γ as a source for high-energy γ rays are investigated. The polarization of the γ's is shown to be negligible at high energies. The spread of γ spectra at a fixed angle due to radiative corrections is investigated. Terms like (απ)ln2(4E2m2) are associated with infrared divergence and disappear with a reasonable energy resolution. The result is very similar to Schwinger's corrections without vacuum polarization. Our result was found to be also usable in the colliding-beam experiment without any modification, under certain conditions.