Photonic probes in nonclassical states, e.g., sub-Poisson, squeezed, and entangled states, provide measurement accuracies surpassing shot-noise and Heisenberg limits. I will review the state of the art in five sensing and imaging applications: photon-correlated imaging, ghost imaging, quantum optical coherence tomography, sub-Rayleigh-resolution imaging, and two-photon interferometric metrology.