I was reading a recent discussion on gravitational lensing, in which it described the bending of light from a distant galaxy as it passed a nearer galaxy to produce two images of the same distant galaxy.
How does that happen? If the distant object is directly behind the lensing object, the light would be bent around it "on all sides"; there shouldn't be two images of the distant object, but a sort of distorted "halo" surrounding the lensing object, correct?
And if the distant object is not directly behind the lensing object, its image would simply be displaced, not divided, correct?
So how does a gravitationally lensing object produce two distinct images of something more distant?