Probability of magnification at the four image positions when microlenses are added. Each color corresponds to one of the positions. The horizontal bars show the observed magnification from Dhawan et al. (2020) (after correcting for extinction) with its uncertainty. The four vertical lines in the bottom of the plot mark the predicted magnification from the macromodel (i.e., without microlenses). The curves show the probability of the magnification when microlenses are included. The curves are computed assuming the source is a Gaussian with FWHM = 5.6 × 10⁻⁴ pc. This size is similar to the extent of the photosphere of a typical SN during its peak emission.