Image (mathematics)

In mathematics, the image of a function is the set of all output values it may produce.

f is a function from domain X to codomain Y. The yellow oval inside Y is the image of f.

More generally, evaluating a given function f at each element of a given subset A of its domain produces a set, called the "image of A under (or through) f ". Similarly, the inverse image (or preimage) of a given subset B of the codomain of f, is the set of all elements of the domain that map to the members of B.

Image and inverse image may also be defined for general binary relations, not just functions.