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. Scientists value every part of the electromagnetic spectrum. X rays are ideal for viewing black hole activity because they are produced close to the source and can escape the region without being absorbed by intervening dust. 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.