Bug 140395 IImage.getID() return null on chart images
When I use image.getID() to retrieve ID of chart image, it always returns null.
engine/org.eclipse.birt.report.engine/src/org/eclipse/birt/report/engine/api/impl/Image.java
public void writeImage( File dest ) throws IOException
	{
		if ( source == IImage.INVALID_IMAGE )
		{
			logger.log( Level.SEVERE, "image source {0} is not valid!", id ); 
			return;
		}
		InputStream input = getImageStream();
		if ( null == input )
		{
			logger.log( Level.SEVERE, "image source {0} is not found!", id ); 
			return;
		}
		
		
		String parent = new File( dest.getAbsolutePath( ) ).getParent( );
		File parentDir = new File( parent );
		if ( !parentDir.exists( ) )
			parentDir.mkdirs( );
		OutputStream output = null;
		try
		{
			output = new BufferedOutputStream( new FileOutputStream( dest ) );
			copyStream( input, output );
		}
		catch ( IOException ex )
		{
			logger.log( Level.SEVERE, ex.getMessage( ), ex );
		}
		finally