Bug 190981 The image id of image in different pages are the same
The id of image generated by the same report item (such as chart) are the same, thought the image contents are in different pages.
engine/org.eclipse.birt.report.engine/src/org/eclipse/birt/report/engine/api/impl/Image.java
{
		return source;
	}
	public void setSource( int source )
	{
		this.source = source;
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.birt.report.engine.api2.IImage#getImageData()
	 */
	public byte[] getImageData( ) throws OutOfMemoryError
	{
		return data;
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.birt.report.engine.api2.IImage#getImageStream()
	 */
	public InputStream getImageStream( )
	{
		switch ( this.source )
		{
			case IImage.FILE_IMAGE :
				try
				{
					URL url = new URL( this.id );
					return new BufferedInputStream( url.openStream( ) );