As an astrophysics nerd, I have to point things out for accuracy as this photo represents one of mankind's most amazing achievements
The black hole itself does not emit light as the escape velocity of the singularity in the center of the hole is greater than the speed of light. However, matter swirling around the event horizon (the point of no return around the hole) is being whipped around at relativistic speeds. Particles crash into each other, creating very powerful x-rays, gamma rays, radio signals, and visible/non-visible light. By photographing this area of space over and over, we can collect a composite picture from any captured photons and eventually put together an outline of the actual black hole.
Black holes went through a process to prove they exist:
- A thought experiment in the 1700's
- A mathematical curiosity in the 1800's
- A mathematical model in the early 1900's
- A theory in in the 1940s
- A discovered candidate in the early 1970s
- Actual photographic evidence in 2019
You're looking at an object that actually breaks the rules of the universe. Amazing to think about.