Bitmap m_Bitmap = new Bitmap(1, 1);private void OpenImage_Click(object sender, EventArgs e){OpenFileDialog openFileDialog = new OpenFileDialog();openFileDialog.Filter = @"Bitmap文件(*.bmp)|*.bmp|Jpeg文件(*.jpg)|*.jpg|所有合适文件(*.bmp;*.jpg)|*.bmp;*.jpg";openFileDialog.FilterIndex = 2;openFileDialog.RestoreDirectory = true;if (DialogResult.OK == openFileDialog.ShowDialog()){m_Bitmap = (Bitmap)Bitmap.FromFile(openFileDialog.FileName, false);}this.pictureBox1.Image = m_Bitmap;}public  bool Brightness(Bitmap b, int nBrightness){if (nBrightness < -255 || nBrightness > 255)return false;BitmapData bmData = b.LockBits(new Rectangle(0, 0, b.Width,b.Height), ImageLockMode.ReadWrite,PixelFormat.Format24bppRgb);int stride = bmData.Stride;System.IntPtr Scan0 = bmData.Scan0;int nVal = 0;unsafe{byte* p = (byte*)(void*)Scan0;int nOffset = stride - b.Width * 3;int nWidth = b.Width * 3;for (int y = 0; y < b.Height; ++y){for (int x = 0; x < nWidth; ++x){nVal = (int)(p[0] + nBrightness);if (nVal < 0) nVal = 0;if (nVal > 255) nVal = 255;p[0] = (byte)nVal;++p;}p += nOffset;}}b.UnlockBits(bmData);return true;}