A representative sample of simulated gravitational lens systems with a high uncertainty in the probability of lensing. The average predicted probability and its uncertainty over 250 iterations for structure 1 is stated above each image. The upper row (lower row) is for a lens population with a set of realistic (uniform) mass model parameters. Each image contains 64 × 64 pixels and is equivalent to a sky-area of 7.68 × 7.68 arcsec².