What we hope to image, actually, is the region bordering the black hole, called the event horizon. This region forms a halo of radiation around the invisible black hole. Once light or matter crosses the event horizon into the black hole, it is lost forever. The force of gravity is so great that even a photon moving at light speed cannot escape the pull. Think of the event horizon as the point of no return.
Light can escape near the event horizon.
Yes, gravity is fantastically powerful. This gravity may distort the light, but nonetheless, light can escape from very close to a black hole and travel across space to our telescopes to tell the tale. Imaging this very region, where matter and energy are put to the ultimate tests of gravity, will be a windfall for the fields of astronomy and physics. Gravity is a force that is all around us, yet scientists know surprisingly little about what produces this force. A black hole is the ultimate gravity laboratory.