The full scientific exploitation of AO images to study resolved stellar populations is still in a nascent stage. This requires pushing to the faint limits and carrying out deep and accurate crowded field photometry and astrometry. The main complexity of AO images is that the correction is never perfect and the PSF always has a complex residual halo around the central core which contains a large fraction of the light. The variations in seeing over short periods of time and anisoplanatism effects create strongly time dependent effects in the PSF. The aim of this study is primarily to test the ability of current photometric packages to be able to cope with a AO PSFs in a number of straightforward but scientifically important examples.