Images of a geometrically thick accretion disk with inner radius r_in = 6M in a Schwarzschild spacetime (left column); in the spacetime of an ultracompact star with surface radius r_st = 2.05M, emitting blackbody radiation at the inner temperature of the accretion flow T_e, in = 8  ×  10¹⁰ K (middle column); or in the same spacetime as the middle column, but with r_st = 2.0005M (right column). As in all figures, the bottom row corresponds to the top row images blurred to the EHT resolution of 20 μas; the dashed blue circle has a diameter of 40 μas (size of the ring feature reported by the EHT) and the blue arrow shows the projected direction of the approaching jet.