asp.net生成缩略图，打水印的类

asp.net生成缩略图，打水印得类，代码如下：

using System;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Drawing.Imaging;

namespace BLL
{
    public class ImageUtil
    {
        public static void addWatermarkImage(Graphics picture, string WaterMarkPicPath, string _watermarkPosition, int _width, int _height)
        {
            Image image = new Bitmap(WaterMarkPicPath);
            int x = 0;
            int y = 0;
            int width = image.Width;
            int height = image.Height;
            string str = _watermarkPosition;
            if (str != null)
            {
                if (!(str == "WM_TOP_LEFT"))
                {
                    if (str == "WM_TOP_RIGHT")
                    {
                        x = (_width - width) - 10;
                        y = 10;
                    }
                    else if (str == "WM_BOTTOM_RIGHT")
                    {
                        x = (_width - width) - 10;
                        y = (_height - height) - 10;
                    }
                    else if (str == "WM_BOTTOM_LEFT")
                    {
                        x = 10;
                        y = (_height - height) - 10;
                    }
                    else if (str == "WM_BOTTOM_MIDDLE")
                    {
                        x = (_width / 2) - (width / 2);
                        y = (_height - height) - 10;
                    }
                    else if (str == "WM_TOP_MIDDLE")
                    {
                        x = (_width / 2) - (width / 2);
                        y = 10;
                    }
                }
                else
                {
                    x = 10;
                    y = 10;
                }
            }
            picture.DrawImage(image, x, y, width, height);
            image.Dispose();
        }

        public static void MakeThumbnail(string originalImagePath, string thumbnailPath, int width, int height, string mode)
        {
            string str;
            Image image = Image.FromFile(originalImagePath);
            int num = width;
            int num2 = height;
            int x = 0;
            int y = 0;
            int num5 = image.Width;
            int num6 = image.Height;
            if (((str = mode) != null) && (str != "HW"))
            {
                if (!(str == "W"))
                {
                    if (str == "H")
                    {
                        num = (image.Width * height) / image.Height;
                    }
                    else if (str == "Cut")
                    {
                        if ((((double)image.Width) / ((double)image.Height)) > (((double)num) / ((double)num2)))
                        {
                            num6 = image.Height;
                            num5 = (image.Height * num) / num2;
                            y = 0;
                            x = (image.Width - num5) / 2;
                        }
                        else
                        {
                            num5 = image.Width;
                            num6 = (image.Width * height) / num;
                            x = 0;
                            y = (image.Height - num6) / 2;
                        }
                    }
                }
                else
                {
                    num2 = (image.Height * width) / image.Width;
                }
            }
            Image image2 = new Bitmap(num, num2);
            Graphics graphics = Graphics.FromImage(image2);
            graphics.InterpolationMode = InterpolationMode.High;
            graphics.SmoothingMode = SmoothingMode.HighQuality;
            graphics.Clear(Color.Transparent);
            graphics.DrawImage(image, new Rectangle(0, 0, num, num2), new Rectangle(x, y, num5, num6), GraphicsUnit.Pixel);
            try
            {
                image2.Save(thumbnailPath, ImageFormat.Jpeg);
            }
            catch (Exception exception)
            {
                throw exception;
            }
            finally
            {
                image.Dispose();
                image2.Dispose();
                graphics.Dispose();
            }
        }
    }

}