  We review the physical origins for possible visible images of the
supermassive black hole M87* in the galaxy M87 and SgrA* in the Milky Way
Galaxy. The classical dark black hole shadow of the maximal size is visible in
the case of luminous background behind the black hole at the distance exceeding
the so-called photon spheres. The notably smaller dark shadow (dark silhouette)
of the black hole event horizon is visible if the black hole is highlighted by
the inner parts of the luminous accreting matter inside the photon spheres. The
first image of the supermassive black hole M87 *, obtained by the Event Horizon
Telescope collaboration, shows the lensed dark image of the southern hemisphere
of the black hole event horizon globe, highlighted by accreting matter, while
the classical black hole shadow is invisible at all. A size of the dark spot on
the Event Horizon Telescope (EHT) image agrees with a corresponding size of the
dark event horizon silhouette in a thin accretion disk model in the case of
either the high or moderate value of the black hole spin, $a\gtrsim0.75$.
