Bug 195335 Multithreads issue
a static hashmap in class HTMLServerImageHandler has not been synchronized which may leads to that the same images are handled(eg: write to disk) multiple times.
engine/org.eclipse.birt.report.engine/src/org/eclipse/birt/report/engine/api/HTMLServerImageHandler.java
boolean needMap )
	{
		try
		{
			File imageFile = File.createTempFile( prefix, ".img" );
			image.writeImage( imageFile );
			String fileName = imageFile.getAbsolutePath( ); 
			if ( needMap )
			{
				String mapID = getImageMapID( image );
				map.put( mapID, fileName );
			}
			return fileName;
		}
		catch ( IOException e )
		{
			log.log( Level.SEVERE, e.getMessage( ), e );
		}
		return "unknow.img";
	}
	/**
	 * returns the unique identifier for the image
	 * 
	 * @param image
	 *            the image object
	 * @return the image id
	 */
	protected String getImageMapID( IImage image )
	{
		if ( image.getReportRunnable( ) != null )