Left panel: color composite HST image of PSZ1-G311 with the observed positions of the 62 observed multiple images marked by circles. The size of the circles scales proportionally with the absolute separation (‖Δ_i‖) between observed and model-predicted positions. The different systems are marked with different colors. Their redshifts are reported in the legend. The white overlaid contours represent the total projected mass–density distribution of our reference model in units of 10⁸ M_⊙ kpc⁻². Right panel: the larger panel shows the distribution of the separations Δx and Δy in RA and Dec between the observed and the model-predicted image positions. The images are colored according to their system. The upper and right panels show the marginalized distributions of the separations Δx and Δy, respectively.