Panel (a): Pan-STARRS g-band image of the galaxy NGC 0718, with the isophotes calculated using Photutils overplotted in white. Panel (b): Cumulative magnitude derived from the previously measured isophotes as a function of the semi-major axis. Blue dots correspond to the integrated magnitude within each isophote, and the dashed black line is a smoothed interpolation of the distribution. The horizontal solid blue line indicates the asymptotic magnitude of the galaxy, and the orange cross marks the semi-major axis at which the cumulative magnitude reaches a value equal to the asymptotic magnitude plus 2.5log(2), corresponding to the effective radius. Panel (c): Cumulative magnitude as a function of the cumulative magnitude gradient. Each blue dot corresponds to a given isophote. The dashed black line shows a linear fit to the data points at the lowest gradients, and the vertical dashed-dotted black line marks the zero gradient. The intercept of the linear fit with the vertical axis is used to estimate the asymptotic magnitude of the galaxy.