Bug 122045 Template should show blank preview when there is no image
Create a template but do not associate an image with it. Place the template in the templates directory. Now, create a new report design. On the second page of the New Report dialog, select the template that has no image. Actual result: The preview appears as a white rectangle with a small red square in the top left. Expected result: The preview appears as a gray background in the preview image area.
UI/org.eclipse.birt.report.designer.ui/src/org/eclipse/birt/report/designer/ui/ReportPlatformUIImages.java
* image descriptor; clients retrieve the image descriptor via
	 * {@link org.eclipse.ui.ISharedImages#getImageDescriptor
	 * ISharedImages.getImageDescriptor()} and are entirely responsible for
	 * managing the image objects they create from it. (This is made confusing
	 * by the historical fact that the API interface is called "ISharedImages".)
	 * </p>
	 * 
	 * @param symbolicName
	 *            the symbolic name of the image
	 * @param descriptor
	 *            the image descriptor
	 */
	public static void declareImage( String symbolicName,
			ImageDescriptor descriptor )
	{
		imageRegistry.put( symbolicName, descriptor );
	}
	/**
	 * Returns the image stored in the workbench plugin's image registry under
	 * the given symbolic name. If there isn't any value associated with the
	 * name then <code>null</code> is returned.
	 * 
	 * The returned Image is managed by the workbench plugin's image registry.
	 * Callers of this method must not dispose the returned image.
	 * 
	 * This method is essentially a convenient short form of
	 * WorkbenchImages.getImageRegistry.get(symbolicName).
	 */
	public static Image getImage( String symbolicName )
	{