Positions of the n = 0 (left panels) and n = 1 (right panels) peaks, observed at 345 GHz and i = 163°, for all the possible emission configurations computed including the real value of the synchrotron pitch angle, θ_B, for a vertical magnetic field in the case of a Schwarzschild black hole (green), a RZ black hole with a₁|_ϵ = 0 = 0.1 (pink), and a RZ black hole with ϵ |_a1 = 0 = 0.1 (violet). Each row corresponds to a different velocity: Keplerian, radial or mixed. Critical curves are represented as dashed lines.