Upon irradiation of a photosensitizer, singlet molecular oxygen has been detected via its a(1)Deltag --> X(3)Sigma(g)(-) phosphorescence with a microscope. Using this tool, a singlet oxygen image with 2.5 mum resolution has been constructed of a phase-separated toluene/water mixture. For the a --> X transition at similar to 7850 cm(-1) (similar to 1270 nm), a lateral resolution of 2.5 mum is close to the diffraction limit of similar to1.5-2.0 mum.