1. A method for associating a photo with a data structure, comprising: displaying the photo at a graphical user interface (GUI); selecting at least one image in the photo relating to a first subject in the photo; in response to selecting the at least one image, creating a first data node that is initially empty; displaying the first data node at the same GUI; at the GUI, graphically moving the selected image to the displayed first data node; and in response to graphically moving the selected image to the displayed first data node, associating the photo with the first data node, so that the first data node is no longer empty; entering photo tagging information in order to identify the displayed photo; displaying a node identifying window at the GUI in response to associating the photo with the first data node, wherein the node identifying information is entered at the node identifying window, and wherein the node identifying information relates to the first subject in the photo and identifies the displayed first data node; after associating the photo with the first data node, creating relationship nodes that are initially empty, each relationship node representing one or more different subjects having a relationship to the first subject; displaying the relationship nodes at the GUI, each relationship node connected to the first data node in order to represent the relationship between the first subject and one of the different subjects; selecting a second image in the photo relating to the one or more different subjects; and at the GUI, graphically moving the selected second image in the photo to one of the displayed relationship nodes, so that the one of the displayed relationship nodes is no longer empty.