Notes. The quoted values are the 50th, 16th and 84th percentiles of the excess and difference for the excess of microlensing time delay distributions. The distributions are computed 10 days after the peak luminosity. The first row shows the values obtained when centering the source on all possible positions in the respective microlensing map, or cross-correlating the individual images distributions in the case of image pairs. The second row shows the values obtained when reweighing the maps by the observed flux excesses in iPTF16geu (see text). Note that we used the unlensed R-band point source template to model the surface brightness time evolution at the center of the disk (i.e. S(0, 0, t)), but choosing another band or even a color curve does not affect the results.