The importance of the visual channel and the diffusion of graphical workstations has turned many image processing environments towards interactivity. Direct manipulation with images, however, is limited because it is difficult to find the right balance between ease of use and generality. The HeROIC library abstracts the concept of region of interest so that users gain a more consistent, flexible, and powerful environment while programmers find an easier way to write their application specific code. A set of standard modules help inspecting images in a variety of methods.