101 × 101 pixel (0.164″ per pixel) gri colour-composite images of the 73 systems in our simulated sample of strongly lensed galaxies. Source i-band magnitudes increase from 20.50 to 25.90 (from left to right and top to bottom). For each system, the i-band ratio Λ_i of the lens to source surface brightness measured at the image locations (introduced and discussed in Sect. 4.2) is overwritten on its image.