Figure: Appearance of a black hole with an accretion disk
By analysing the same effect of the bending of light rays, we can try to guess the appearance of a black hole with an accretion disk.
As shown in this picture, a black hole would appear hat-shaped, because of the bending of light.
Credit: J-A. Marck/J-P. Luminet
Source: http://nrumiano.free.fr/Estars/b_holes.html