IFigure graph = ....my graph
Image img = new Image(Display.getDefault(), graph.getBounds().width, graph.getBounds().height);
final GC imageGC = new GC(img);
Display.getDefault().syncExec(new Runnable() {

	public void run() {
	    graph.paint(new SWTGraphics(imageGC));
	}
});
imageGC.dispose();

    public Image createScaledImage(GraphicalViewer graphicalViewer, double scale) {
        IFigure figure = ((FreeformGraphicalRootEditPart)graphicalViewer.getRootEditPart()).getLayer(LayerConstants.PRINTABLE_LAYERS);
        Rectangle extents = figure.getBounds().getCopy();
        
        Image image = new Image(Display.getDefault(), (int)(extents.width * scale), (int)(extents.height * scale) );
        GC gc = new GC(image);
        SWTGraphics swtGraphics = new SWTGraphics(gc);
        Graphics graphics = swtGraphics;
        
        // If scaled, then scale now
        if(scale != 1) {
            graphics = new ScaledGraphics(swtGraphics);
            graphics.scale(scale);
        }
        
        // Compensate for negative co-ordinates
        graphics.translate(extents.x * -1, extents.y * -1);

        // Paint onto graphics
        figure.paint(graphics);
        
        // Dispose
        gc.dispose();
        graphics.dispose();
        if(swtGraphics != graphics) {
            swtGraphics.dispose();
        }
        
        return image;
    }