We present a microscopic theoretical analysis of time and spatially resolved photoluminescence of naturally occurring quantum dots induced by monolayer fluctuations in the thickness of semiconductor quantum wells. The analysis is based on a recently developed theoretical tool for spatially-resolved photoluminescence spectroscopy in semiconductor quantum structures. The theoretical framework here presented allows to study the influence of temperature and spatial resolution on the detected images. We find that the carrier recombination dynamics is significantly affected by thermal populations in optically inactive or poorly active exciton states. The presence of these states slows-down radiative recombination, determining an increase of the photoluminescence decay time as a function of temperature in a wide temperature range, in agreement with recent experimental results. We investigate these effects in symmetric dots displaying dark excited states.