Q&A: Black Holes

Q:
If light cannot escape black holes, how can we take pictures of them?

A:
You are correct that light can't escape a black hole. What we can see in astronomical images is light from material that is heated up when it gets close to a black hole. This material can glow very brightly, especially in ultraviolet light and X-rays.

Please see: http://chandra.harvard.edu/xray_sources/blackholes.html for more details.