Lensing system and regions for mask creation. Top: image cutout of J2100-4452 to illustrate its different components which are modeled with our automation code. Bottom: image cutout of J2100-4452 with regions provided by the user to create the masks. The region required for creating the arc mask, which covers the light of the lensed quasar and arcs, is plotted in red. For the lens mask, the user provides the region(s) of the surrounding luminous objects (green) that contain the pixels that are ignored by the model.