  We calculate the total photoabsorption cross section on nuclei in the energy
range from 300 MeV to 1 GeV within the framework of a semi-classical phase
space model. Besides medium modifications like Fermi motion and Pauli blocking
we focus on the collision broadening of the involved resonances. The resonance
contributions to the elementary cross section are fixed by fits to partial wave
amplitudes of pion photoproduction. The cross sections for $N \, R \to N \, N$,
needed for the calculation of collision broadening, are obtained by detailed
balance from a fit to $N \, N \to N \, N \, \pi$ cross sections. We show that a
reasonable collision broadening is not able to explain the experimentally
observed disappearance of the $D_{13}(1520)$-resonance in the photoabsorption
cross section on nuclei.
