1. A method for categorizing a plurality of unlabeled images, the method comprising: generating a first spatial-contextual model to represent a first image, the first spatial-contextual model having a plurality of interconnected nodes arranged in a first pattern of connections with each node connected to at least one other node; generating a second spatial-contextual model to represent a second image, the second spatial-contextual model having a plurality of interconnected nodes arranged in the first pattern of connections; determining a relationship of adjacent nodes that each node is connected with in the first pattern of connections; and calculating a distance between corresponding nodes in the first spatial-contextual model and the second spatial-contextual model based on the relationship of adjacent connected nodes to determine a distance between the first image and the second image.