def plot_graph(self, G):
    plt.figure(figsize=(4, 3))
    nx.draw(G, with_labels=True, node_color='lightblue', font_weight='bold')
    plt.axis('off')

    # Save to BytesIO buffer
    buf = io.BytesIO()
    plt.savefig(buf, format='png', bbox_inches='tight', pad_inches=0.1)
    plt.close()

    # Reset buffer and open as PIL image
    buf.seek(0)
    image = Image.open(buf)
    return image, buf  # Return image and buffer for download