image (function)

For a function $f\subseteq A\times B$, the image $f[A]$ is the set of all possible values of $f$. More formally, the image of $f$ is the set of all $y\in B$ such that $f(x)=y$ for any $x\in A$. If the domain and codomain are two disjoint sets, then the image can be described as the set of all elements to which there is an arrow pointing from the domain. Note that the image is a subset of codomain.