Results from the galaxy model fits for test I using the native HST/ACS and Euclid/VIS pixel scales, for a number of galaxies N_gal ≃ 10⁴, as described in Sect. 5.1. The fitted parameters R_e, fit[″], F_fit[mag], and n_fit are shown as a function of the input R_e in arcsec for both the output galaxies D and E and for three values of the S/N. The data points are the average over the number of galaxies in each sample. The error bars, representing the 1σ uncertainty on the mean, are smaller than the size of the points and, thus, they are not visible.