ScrollImage is kind of like Flash ScrollPane component. The component takes any image url and loads the image putting scrollbars around it to allow the image to be scrolled. While the same effect can be created by using the Image inside a Canvas container, this implementation is much more efficient since its not creating a heavier container object.
I wrote the ScrollImage container as I was trying to understand the basic ScrollControlBase class that all controls that have scrollable content use. If you are a Flex developer, the source of the code should be very instructional. I have commented it out a bit and most of the code is self explanatory. Check the component out here and view the source here.