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
if ( imageDescriptor == null )
			{
				imageDescriptor = getImageDescriptor( IReportGraphicConstants.ICON_ELEMENT_EXTENDED_ITEM );
			}
		}
		else if ( model instanceof DesignElementHandle )
		{
			imageDescriptor = getImageDescriptor( ( (DesignElementHandle) model )
					.getElement( ).getDefn( ).getName( ) );
		}
		return imageDescriptor;
	}
	/**
	 * Returns the ImageRegistry.
	 */
	public static ImageRegistry getImageRegistry( )
	{
		return imageRegistry;
	}
	/**
	 * Initialize the image registry by declaring all of the required graphics.
	 * This involves creating JFace image descriptors describing how to
	 * create/find the image should it be needed. The image is not actually
	 * allocated until requested.
	 * 
	 * Prefix conventions Wizard Banners WIZBAN_ Preference Banners PREF_BAN_
	 * Property Page Banners PROPBAN_ Enable toolbar ETOOL_ Disable toolbar
	 * DTOOL_ Local enabled toolbar ELCL_ Local Disable toolbar DLCL_ Object
	 * large OBJL_ Object small OBJS_ View VIEW_ Product images PROD_ Misc
	 * images MISC_