Quality lost after overlaying rectangle on image

I am losing image quality when i overlay a rectangle onto an image. How can i stop this?

using (Aspose.Imaging.Image image = Aspose.Imaging.Image.Load(file))
{
Graphics graphic = new Graphics(image);

                    graphic.FillRectangles(new Aspose.Imaging.Brushes.SolidBrush(Aspose.Imaging.Color.Black), rectangles);

                    image.Save();
                }

@smooney1234,

I have observed the issue shared by you and request you to please share the source file along with generated output and desired output file. We will be able to investigate the issue further on our end on provision of requested information.

got it sorted thanks. had to update the resolution

@smooney1234,

Its good to know that your issue has been resolved.