  The low $p_T$ direct photon production from a variety of the hadronic sources
is studied within the microscopic HSD transport approach for p+C, p+Pb and
Pb+Pb collisions at 160 A GeV. The direct photon emission from elementary
hadronic scatterings as well as meson-meson bremsstrahlung are incorporated.
The influence of in-medium effects such as a collisional broadening of the
vector-meson spectral functions on the photon emission rate is found to be
hardly observable in the final spectra which are dominated by bremsstrahlung
type processes. The uncertainties in the subtraction of the 'background' from
the photon decay of hadronic resonances inside the hot and dense fireball is
investigated, additionally. Our findings are relevant for the interpretation
and extraction of experimental data on direct photon production at low $p_T$.
