We are using steady state imaging techniques based on neutron radiography for in situ fuel cell diagnostics. Through plane neutron radiography (neutron beam perpendicular to the membrane plane) can resolve the distribution of liquid water over the fuel cell area. This technique has been applied for several years at PSI. To resolve the distribution of water across the fuel cell structure, in plane imaging has to be used, which implies very high requirements on resolution. Recent improvements of the imaging method, pixel resolution of a low as 2.5 μm could be reached.