C#图片裁剪与大小缩放

public Bitmap CutBitmap(Bitmap b, int left, int top, int Width, int Height)//对图片进行裁剪      

{
            Bitmap bm = b;
            Graphics g = Graphics.FromImage(bm);
            g.DrawImage(b, new Rectangle(0, 0, bm.Width, bm.Height), new Rectangle(left, top, Width, Height), GraphicsUnit.Pixel);
            g.Dispose();
            Bitmap bmp=ResizeBitmap(bm, 150, 150);
            return bmp;
}
public Bitmap ResizeBitmap(Bitmap b, int dstWidth, int dstHeight)//对像片进行平滑缩放处理
{
            Bitmap dstImage = new Bitmap(dstWidth, dstHeight);
            System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(dstImage);

//   设置插值模式
            g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.Bilinear;

//   设置平滑模式
            g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;

g.DrawImage(b,
                new System.Drawing.Rectangle(0, 0, dstImage.Width, dstImage.Height),
                new System.Drawing.Rectangle(0, 0, b.Width, b.Height),
                System.Drawing.GraphicsUnit.Pixel);
            g.Save();
            g.Dispose();

return dstImage;
}