In this contribution we discuss image quality in the context of the visuo-cognitive system as an information-processing system. To this end, we subdivide the information-processing as performed by the visuo-cognitive system into three distinct processes: (1) the construction of a visual representation of the image, (2) the interpretation of this representation by means of a confrontation with memory, and (3) task-directed semantic processing of the interpreted scene to formulate a proper response.A successful completion of these processes can be ensured only when two main requirements are satisfied: (1) the visual representation of the image should be sufficiently precise, and (2) the degree of correspondence between the visual representation and “knowledge of reality” as stored in memory should be high.We then relate these requirements to the attributes “usefulness” and “naturalness” of the image and give a functional description of image quality in terms of naturalness and usefulness. To conclude, experimental results supporting this description of image quality will be discussed.