C#サムネイルの生成

using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Text;
using System.IO;
using System.Drawing;

public partial class _Default : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        MakeSmallImg("F:\\myproject\\web\\2006092809470622.jpg", Server.MapPath(@"Photo\a.jpg"), 100, 100, "Cut");
    }

    /// <summary>
    ///      
    /// </summary>
    /// <param name="originalImagePath">    （    ）</param>
    /// <param name="thumbnailPath">     （    ）</param>
    /// <param name="width">     </param>
    /// <param name="height">     </param>
    /// <param name="mode">        </param>　　
    public void MakeSmallImg(string originalImagePath, string thumbnailPath, int width, int height, string mode)
    {
        
        System.Drawing.Image originalImage = System.Drawing.Image.FromFile(originalImagePath);
        int towidth = width;
        int toheight = height;
        int x = 0;
        int y = 0;
        int ow = originalImage.Width;
        int oh = originalImage.Height;

        switch (mode)
        {
            case "HW"://      （    ）　　　　　　　　
                break;
            case "W"://   ，    　　　　　　　　　　
                toheight = originalImage.Height * width / originalImage.Width;
                break;
            case "H"://   ，    
                towidth = originalImage.Width * height / originalImage.Height;
                break;
            case "Cut"://      （   ）　　　　　　　　
                if ((double)originalImage.Width / (double)originalImage.Height > (double)towidth / (double)toheight)
                {
                    oh = originalImage.Height;
                    ow = originalImage.Height * towidth / toheight;
                    y = 0;
                    x = (originalImage.Width - ow) / 2;
                }
                else
                {
                    ow = originalImage.Width;
                    oh = originalImage.Width * height / towidth;
                    x = 0;
                    y = (originalImage.Height - oh) / 2;
                }
                break;
            default:
                break;
        }
        //    bmp  
        System.Drawing.Image bitmap = new System.Drawing.Bitmap(towidth, toheight);

        //      
        Graphics g = System.Drawing.Graphics.FromImage(i);

        //        
        g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;

        //     ,         
        g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;

        //             
        g.Clear(Color.Transparent);

        //                      
        g.DrawImage(originalImage, new Rectangle(0, 0, towidth, toheight),
          new Rectangle(x, y, ow, oh),
          GraphicsUnit.Pixel);

        try
        {
            // jpg       
            bitmap.Save(thumbnailPath, System.Drawing.Imaging.ImageFormat.Jpeg);
        }
        catch (System.Exception e)
        {
            throw e;
        }
        finally
        {
            originalImage.Dispose();
            bitmap.Dispose();
            g.Dispose();
        }
    } 

}