This document summarizes various content-based image retrieval techniques using clustering methods for large datasets. It discusses clustering algorithms like K-means, hierarchical clustering, graph-based clustering and a proposed hybrid divide-and-conquer K-means method. The hybrid method uses hierarchical and divide-and-conquer approaches to improve K-means performance for high dimensional datasets. Content-based image retrieval relies on automatically extracted visual features like color, texture and shape for image classification and retrieval.