Example of a two-component best-fit model to the grizy images of a simulated strongly lensed galaxy–galaxy system. From top to bottom: colour-composite gri, riz, and izy images. The first column from the left shows the simulated image. The second column shows the PSF-convolved best-fit image. The third and fourth columns show the best-fit lens-only and the best-fit source-only light profiles. The last column shows the residuals (best-fit-subtracted original image). The contaminants were masked by running the SExtractor on the i-band image.