Media hyped black hole images will show a
whole lot of nothing.  Look at the simulations
put out by the research team showing what they expect to find, nothing,
at least at the location of the black hole.   Which is just fine.  A black hole
is a region of space time from which light cannot escape.  The escape velocity for
their gravitational field exceeds the speed of light.  In relativistic terms their
effect on space time is such that falling towards the center of the black hole
is as inevitable as the flow of time in the forward direction. As such the base
standard expectation of a black hole image is to see nothing.   

What is interesting is what we will see surrounding that
nothingness.

Although I would not be completely surprised if the actual image
shows the black hole to “shine” from light that just barely skims the event
horizon.  The path of the light having been bent into our line of sight from
some distant star or stars.

CLICK FOR IMAGE. image Credit: Chi-Kwan Chan, Event Horizon Telescope.

This image highlights the simulates the expected features of
the accretion disk and outflow near Sgr A*which would result from combining
images taken at different wavelengths/frequencies of light.  Precise
observations of the accretion disk and outflow near a black hole could help us
to refine our models of gravity by testing them in a regime of intense
gravitational fields.  Precise enough observations of light that just barely escapes
the event horizon could, someday, tell us something about the structure of
space time and of QFT interactions in a region where both gravity and quantum
are important.   Such images could, someday, provide indirect test of theories
which seek to unify general relativity with quantum field theory.

For now, let it be enough to marvel at having any image
at all of such an elusive region of space-time as a black hole. This will
be a great achievement worthy of all the fanfare it gets no matter what it
finds.

Scientific prediction:  We will see results which exactly correspond
to completely classical General Relativity with no hint of physics beyond any
standard models.  Never bet against Einstein.