This site contains: mathematics courses and book; covers: image analysis, data analysis, and discrete modelling; provides: image analysis software. Created and run by Peter Saveliev.

From Intelligent Perception

The image of a function is the set of all of its values, aka the range.

Also, given sets $X$ and $Y$, subset $A$ of $X$, and a function $f:X \rightarrow Y$. Then the image of $A$ under f is $$f(A)=\{ f(x):x\in A\} .$$