Zoom-in view of the reconstructed source light and convergence perturbations from the JWST NIRCam observation of SPT0418-47. Left panel: reconstruction of the source light distribution, accompanied by the caustics depicted by the solid lines. Right panel: convergence perturbations through the relative difference between the reconstructed convergence and the parametric (PIE) model. The solid contour lines are the lensed source light distribution contours, cf. Fig. 6.