We discuss imaging sources from low relative-velocity correlations in heavy-ion reactions. When the correlation is dominated by interference, we can obtain the images by Fourier transforming the correlation function. In the general case, we may use the method of optimized discretization. This method stabilizes the inversion by adapting the resolution of the source to the experimental error and to the measured velocities. The imaged sources contain information on freeze-out density, phase-space density, and resonance decays, among other things.