Brightness comparison between original and noisy image is shown for a sample redshift 5, 7 & 10 galaxies with size offset at S/N =5. The bottom row shows the mean luminosity of pixels at each radius (y-axis) calculated by finding pixel luminosities at the edge of the aperture and dividing it by circumference) plotted against the radius (x-axis) for the normalised images. The centre for these luminosities is assumed as the centre of potential as defined in the simulations. The red lines indicate the maximum brightness and the green line shows the median brightness. The blue solid and dashed lines show the r20 of original and noisy image respectively. The purple solid and dashed lines show the r80 of original and noisy images respectively. Panel for z = 5 shows the case of underestimation, z = 7 of near parity and z = 10 shows an overestimation.