  It has been found in recent heavy-ion experiments that the second and the
third flow harmonics of direct photons are larger than most theoretical
predictions. In this study, I construct effective parton phase-space
distributions with in-medium interaction using quasi-particle models so that
they are consistent with a lattice QCD equation of state. Then I investigate
their effects on thermal photons using a hydrodynamic model. Numerical results
indicate that elliptic flow and transverse momentum spectra are modified by the
corrections to Fermi-Dirac and Bose-Einstein distributions.
