C# PNG转BMP

System.Drawing.Image PngImg = System.Drawing.Image.FromFile(@"C:\Users\ATQ\Desktop\WebApplication1\00A.png");
                Bitmap myImage = new Bitmap(PngImg.Width, PngImg.Height, PixelFormat.Format32bppRgb);
                using (Graphics g = Graphics.FromImage(myImage))
                {
                    g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic;
                    g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
                    g.CompositingQuality = System.Drawing.Drawing2D.CompositingQuality.HighQuality;
                    g.DrawImage(PngImg, 0, 0);
                }