1. A system for real world event summarization with microblog data, the system comprising: one or more processors and a memory, the memory being a non-transitory computer-readable medium having executable instructions encoded thereon, such that upon execution of the instructions, the one or more processors perform operations of: collecting microblog image posts related to a real world event based on an event tag; identifying nodes and edges of a heterogeneous network based on the microblog image posts, wherein the heterogenous network is a graph of different node types, the different node types comprising post nodes, tag nodes, user nodes, and image nodes, and wherein the heterogenous network comprises a plurality of unions of the different node types; ranking the nodes; and extracting images from top-ranked nodes for real world event summarization.