  We consider directly emitted and hadronic decay photons from event-by-event
hydrodynamic simulations. We compute the direct photon anisotropic flow
coefficients and compare with recent experimental measurements. We find that it
is crucial to include the photon multiplicity as a weighting factor in the
definition of $v^\gamma_n$. We also investigate the sensitivity of the direct
photon spectrum and elliptic flow to the theoretical uncertainty of the photon
emission rate in the quark-hadron transition region and to the pre-equilibrium
dynamics of relativistic heavy-ion collisions.
