Images of an accretion disk as viewed at three inclinations i = 30° (a), 60° (b), and 80° (c). The coordinates on the sky are given in units of R_S. Contours show the images of rings of equal radii r (from 3 to 15, with a step of 3) and equal azimuths φ (every 30°). Black solid contours correspond to the exact calculations of α(ψ), while the white dashed contours (almost fully overlapping with the black ones) are for the approximation (35). The colors reflect the logarithm of g⁴t⁴(u)a_es(ζ′), which is proportional to the bolometric intensity. The blue sticks give polarization computed using approximate light bending expression (35), with their length being proportional to the PD and their position angle is given by the PA. Exact calculations shown by green sticks are nearly indistinguishable from the approximation.