Gamma-ray light curves of EIC emission at 1 GeV in the late internal dissipation model for GRB afterglows, caused by Compton scatterings of X-ray photons by electrons accelerated at the external shock. For comparison, light curves of synchrotron and SSC emission are also shown. The parameter set is the same as that used in the caption of Figure 3. The Fermi/LAT sensitivity is overlaid. Note that the attenuation by pair creation both inside and outside the source is taken into account.