Bug 313459 Problem with % when generating images in tables.
See the attached BirtProject, it has two reports. Each identical except for this difference: The image width/height is set to a %age value (50%) in one (TestImage.rptdesign) and not-set in the other (TestImageWorking.rptdesign). TestImage.rptdesign does not display the image in pdf, but works fine in html. TestImageWorking.rptdesign shows the image in both pdf and html. The %age setting seems to cause the problem in pdf format.
engine/org.eclipse.birt.report.engine/src/org/eclipse/birt/report/engine/layout/pdf/util/PropertyUtil.java
if ( 0 == resolution )
		{
			ReportDesignHandle designHandle = content.getDesign( )
					.getReportDesign( );
			resolution = designHandle.getImageDPI( );
		}
		if ( 0 == resolution )
		{
			resolution = getScreenDpi( );
		}
		if ( 0 == resolution )
		{
			resolution = 96;
		}
		return resolution;
	}
	public static int getRenderDpi( IContent content, int renderOptionDpi )
	{
		return getRenderDpi( content.getReportContent( ), renderOptionDpi );
	}
	private static int screenDpi = -1;
	/**
	 * Get the screen DPI. If the return value is 0, it means the screen dpi is
	 * invalid, otherwise it should be between 96 and 120.
	 * 
	 * @return the screen DPI.
	 */
	private static int getScreenDpi( )
	{
		if ( -1 == screenDpi )