Sample of simulated lenses: three pairs are generated from power-law, cored power-law, and composite lens models. The color scale is logarithmic and is the same for all images. Identifiers associated to each lens are also indicated. Refer to Sect. 6.2 for a description of these simulations. Model #6, although composite, is chosen so that the total mass profile resembles a power law in the region of the Einstein radius.