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/ReportDesignHandle.java
catch ( SemanticException e )
		{
			assert false;
		}
	}
	/**
	 * Sets the base directory to use when computing relative links from this
	 * report. Especially used for searching images, library and so.
	 * 
	 * @param base
	 *            the base directory to set
	 */
	public void setBase( String base )
	{
		try
		{
			setProperty( BASE_PROP, base );
		}
		catch ( SemanticException e )
		{
			assert false;
		}
	}
	/**
	 * Sets the script called at the start of the Factory after the initialize( )
	 * method and before opening the report document (if any).
	 * 
	 * @param value
	 *            the script to set.
	 */