In terms of the 2D picture control, it is an indicator like any other in that it displays data on a VI's front panel. The difference is that in this case, the data is a graphical image.
To create an image for it to draw, LV provides a palette of primative functions for drawing simple things like lines, circles or rectangles. Once you learn how to work with the LV development environment, you need to experiment with those primative drawing functions and learn how to combine them to draw what you want your various SCADA objects to look like.
Mike...