Logarithmic intensity distribution of a source consisting of four Sérsic profiles, described in Sect. 4.1, simulating a galaxy with resolved brightness features (left). Multiple images of this source generated by the SIE lens introduced in Wagner (2017) and described in Sect. 4.2 (right). The lens centre is indicated by a red cross; the small red circle marks the point through which the horizontal and vertical intensity profiles run (shown beneath andto the right of the picture).