1. A method for representing image data as a graph, comprising: receiving image data; receiving one or more seed points within the image data; computing image features based on the received image data and the seed points; representing the image data as a graph wherein each pixel of the image data is represented as a node and edges connect nodes representative of proximate pixels of the image data; and establishing edge weights for the edges of the graph using a classifier that takes as input, one or more of the computed image features, wherein each of the above steps is performed by a computer system.