silverlight 2 includes deep zoom, a technology derived from microsoft live labs' seadragon. it allows users to zoom into, or out of, an image (or a collage of images), with smooth transitions, using the mouse wheel. the images can scale from 2 or 3 megapixels in resolution into the gigapixel range, but the user need not wait for it to be downloaded entirely; rather, silverlight downloads only the parts in view, optimized for the zoom level being viewed. beta 2 onwards, deep zoom uses an xml-based file format.