Bug 150347 Support binary stream as preview image.
See 144843. We need model to save binary strame as report preview image. Currently, preview image is an external image. Maybe need a type to distinguish preview image type.
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/api/command/NameSpaceEvent.java
*/
	public static final int ELEMENT_RENAMED = 3;
	/**
	 * The name space that changed.
	 */
	private int nameSpaceID = 0;
	/**
	 * The action which causes this event.
	 */
	private int action;
	private DesignElement element;
	/**
	 * Constructor.
	 * 
	 * @param root
	 *            the root element
	 * @param id
	 *            the id of the name space that changed
	 * @param theAction
	 *            the action causing this event
	 */
	public NameSpaceEvent( DesignElement root, int id, int theAction )
	{
		super( root );
		nameSpaceID = id;
		action = theAction;
	}
	/**
	 * Constructor.
	 *