> For the complete documentation index, see [llms.txt](https://mandober.gitbook.io/math-debrief/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://mandober.gitbook.io/math-debrief/260-function-theory/topics/image.md). # Image The image of a function is the set of all output values it may produce. 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 relations, not just functions.