Principal axes FWHMs as a function of time for the simulation of Sgr A^* in Fig. 2 (Mościbrodzka & Gammie 2018). The solid lines show sizes for the simulation, the dotted lines show sizes for the simulation including the effects of interstellar scattering (Johnson 2016; Johnson et al. 2018). The scattering major axis is aligned with the source minor axis, and thus the scattering kernel slightly dominates the minor axis size, which stabilizes the minor axis FWHM time series. The sizes were obtained from measurements of the image second moment per frame. For all four size trends, the deviation about the mean size is < 10%.