[转载]ASP.NET MVC 3 开发的20个秘诀（十二）[20 Recipes for Programming MVC 3]：缩放图片尺寸创建缩略图

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.IO;
using System.Drawing;
using System.Drawing.Drawing2D;
namespace MvcApplication4.Utils
{
    public static class FileUpload
    {
        public static char DirSeparator =
        System.IO.Path.DirectorySeparatorChar;
        public static string FilesPath = "Content" +
        DirSeparator + "Uploads" + DirSeparator;
        public static string UploadFile(HttpPostedFileBase file)
        {
            ...
            // 保存缩略图
            ResizeImage(file, 150, 100);
            ...
        }
        public static void DeleteFile(string fileName)
        {
            // 如果没有指定文件名就什么都不做
            if (fileName.Length == 0) return;
            // 设置删除路径
            string path = FilesPath + DirSeparator + fileName;
            string thumbPath = FilesPath + DirSeparator +
            "Thumbnails" + DirSeparator + fileName;
            RemoveFile(path);
            RemoveFile(thumbPath);
        }
        private static void RemoveFile(string path)
        {
            // 检查文件是否存在
            if (File.Exists(Path.GetFullPath(path)))
            {
                // 删除文件
                File.Delete(Path.GetFullPath(path));
            }
        }
        public static void ResizeImage(HttpPostedFileBase file,
        int width, int height)
        {
            string thumbnailDirectory =
            String.Format(@"{0}{1}{2}", FilesPath,
            DirSeparator, "Thumbnails");
            // 检查目标文件夹是否存在
            if (!Directory.Exists(thumbnailDirectory))
            {
                // 假如文件夹不存在就创建它
                Directory.CreateDirectory(thumbnailDirectory);
            }
            // 设置缩略图保存路径
            string imagePath =
            String.Format(@"{0}{1}{2}", thumbnailDirectory,
            DirSeparator, file.FileName);
            // 将文件流保存到磁盘
            FileStream stream = new FileStream(Path.GetFullPath(
            imagePath), FileMode.OpenOrCreate);
            // 缩放上传的文件
            Image OrigImage = Image.FromStream(file.InputStream);
            // 创建缩略图对象
            Bitmap TempBitmap = new Bitmap(width, height);
            // 创建缩略图画质
            Graphics NewImage = Graphics.FromImage(TempBitmap);
            NewImage.CompositingQuality =
            CompositingQuality.HighQuality;
            NewImage.SmoothingMode =
            SmoothingMode.HighQuality;
            NewImage.InterpolationMode =
            InterpolationMode.HighQualityBicubic;
            // 创建Rectangle对象进行绘制
            Rectangle imageRectangle = new Rectangle(0, 0,
            width, height);
            NewImage.DrawImage(OrigImage, imageRectangle);
            // 保存缩略图
            TempBitmap.Save(stream, OrigImage.RawFormat);
            // 释放资源
            NewImage.Dispose();
            TempBitmap.Dispose();
            OrigImage.Dispose();
            stream.Close();
            stream.Dispose();
        }
    }
}