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
* <li><code>REMOVE</code>
	 * </ul>
	 * 
	 * @return the action causing this event.
	 */
	public int getAction( )
	{
		return action;
	}
	/**
	 * Returns the id of the name space that changed.
	 * 
	 * @return the id of the name space that changed.
	 */
	public int getNameSpaceID( )
	{
		return nameSpaceID;
	}
	/**
	 * Returns the element whose name is changed for
	 * <code>ELEMENT_RENAMED</code>. Otherwise, return null.
	 * 
	 * @return Returns the element.
	 */
	public DesignElement getElement( )
	{
		return element;
	}
}