Right: set of mock lensed images produced by our fiducial lens model (using a grid of source positions shown in the first quadrant of the left panel). The color-coding shows the offset in arcseconds, between the original image positions and those found with the power-law model. Left: first quadrant (upper right): grid of source positions lensed with our fiducial model to produce the images shown in the right panel. The color-coding indicates the χ² associated with each source, assuming an astrometric uncertainty on the image position of σ_θx,y = 0.004′′. In the third quadrant (lower left), the sources do not have corresponding lensed images on the right panel, and are colored as a function of the ratio of their total magnification as derived with the power-law and the fiducial models (i.e., ).