  We present a calculation of e^+e^- production in $\gamma A$ reactions at MAMI
and TJNAF energies within a semi-classical BUU transport model. Dilepton
invariant mass spectra for $\gamma$C, $\gamma$Ca and $\gamma$Pb are calculated
at 0.8, 1.5 and 2.2 GeV. We focus on observable effects of medium modifications
of the $\rho$ and $\omega$ mesons. The in-medium widths of these mesons are
taken into account in a dynamical, consistent way. We discuss the transport
theoretical treatment of broad resonances.
