this.pictureBox1.Image.RotateFlip(RotateFlipType.Rotate90FlipNone);
this.pictureBox1.Refresh();
逆时针旋转图片
this.pictureBox1.Image.RotateFlip(RotateFlipType.Rotate270FlipNone);
this.pictureBox1.Refresh();
this.pictureBox4.Image.RotateFlip(RotateFlipType.RotateNoneFlipX); //左右镜像
还有180,上下镜像等