The image formation mechanism in piezoresponse force microscopy (PFM) of capacitor structures is analyzed. We demonstrate that the spatial resolution is a bilinear function of film and top electrode thicknesses and derive the corresponding analytical expressions. For many perovskites, the opposite contributions of d(31) and d(33) components can result in anomalous domain wall profiles. This analysis establishes the applicability limits of PFM for polarization dynamics studies in capacitors and applies them to other structural probes, including focused x-ray studies of capacitor structures. (c) 2008 American Institute of Physics.