C#修改图片分辨率

public static Bitmap KiResizeImage(Bitmap bmp, int newW, int newH)  
        {  
            try  
            {  
                Bitmap b = new Bitmap(newW, newH);  
                Graphics g = Graphics.FromImage(b);  
                // 插值算法的质量   
                g.InterpolationMode = InterpolationMode.HighQualityBicubic;  
                g.DrawImage(bmp, new Rectangle(0, 0, newW, newH), new Rectangle(0, 0, bmp.Width, bmp.Height), GraphicsUnit.Pixel);  
                g.Dispose();  
                return b;  
            }  
            catch  
            {  
                return null;  
            }  
        }