With the advance of networking technologies, the widespread use of handheld devices not only enables instant access of required information but also shortens the distance among acquaintances. Nowadays one can easily share their photos on the Internet right after the photos are taken. With an increasing amount of images, a challenging problem for computer algorithms is to discover the visual-concept embedded within an image. Instead of modeling this problem as a classification process which attempts to categorize images into different pre-defined classes, we propose in this work to start with identifying similar image patches. Specifically, we adopt the technique of mining association rules to construct evident relationships among image patches so as to discover identical visual-concepts from online images.