Einstein's rings, also known as gravitational lensing, occur when the light from a distant object is bent and distorted by the gravitational field of a massive object, such as a galaxy or a black hole. While gravitational lensing can certainly magnify and distort the appearance of the background objects, it does not directly contain any missing information or reveal what is inside a black hole.
When a black hole is involved in gravitational lensing, it can create a phenomenon known as an Einstein ring. This occurs when the light from a background source, such as a distant galaxy, is bent around the black hole, forming a ring-like structure. The size and shape of the Einstein ring depend on the mass and alignment of the black hole with respect to the observer and the source of light.
However, it's important to note that the presence of an Einstein ring does not provide information about the internal structure or contents of the black hole itself. The dark disk you mentioned is likely a representation of the event horizon, the boundary beyond which no light can escape the gravitational pull of the black hole.
The study of black holes is a fascinating area of research in astrophysics, and while gravitational lensing can offer insights into the effects of their immense gravitational fields, direct observation of their interiors remains a challenge due to the nature of black holes. Current understanding suggests that the information about an object falling into a black hole is lost to outside observers, a concept known as the black hole information paradox. Ongoing research and theoretical developments aim to address this fundamental question in physics.