We present a methodology for pictorial data management based upon the theory of symbolic projections. In this methodology, the spatial knowledge structure consists of an image database, symbolic projections representing the spatial relations among objects or sub-objects in an image, and rules to derive complex spatial relations from the generalized 2-D string representation of the symbolic projections. Based upon this methodology, we developed a prototype knowledge-based pictorial database management system, which supports spatial reasoning, flexible pictorial information retrieval, visualization and manipulation.