The node graph defines the workflow of an image.
In a typical nodes graph, images flow from node to node through connections, where each node modifies the input image. Other types of data can flow, like colors and values.
Nodes are the main processing units in the nodes graph. Nodes receive an input values through the input sockets, and return output values through the output sockets.
Nodes can have no input, as the Generate: Reader node, which reads a bitmap from disk and returns an image to the graph output. Nodes can have no output, as the Writer node, which is used by the user interface to display the final image.
Nodes can be connected to each other using connections. A connection goes from the output of one node to the input of another node.