Properties of the four images of a source placed directly behind the lens center, for SPEMDs and corresponding SPEPs. Several different power‐law indices η are considered. Left: Distance y of the images on the y‐axis over the distance x of the images on the x‐axis. Right: Magnification ratio A_y/A_x of the two types of images. In each case the appropriate quantity is plotted as a function of ellipticity, with the SPEMD as the solid curve and the SPEP as the dashed curve.