ASP.NET创建缩略图

在学习过程中发现如果要上传的照片很大的话，速度会很慢，所以采用了在上传照片时同时上传缩略图的方式，这样就可以既不影响多个图片的浏览，又不影响查看具体的图片。
需要用到的命名空间：
using System.Drawing;
using System.IO;
using System.Drawing.Imaging;
#region 保存上传文件，方法名：UploadSave(string asFilePath, FileUpload asFileUpload)
/// <summary>
///  保存上传文件
/// </summary>
/// <param name="asFilePath">保存到的服务器路径</param>
/// <param name="asFileUpload">上传控件</param>
/// <returns></returns>
public int UploadSave(string asFilePath, FileUpload asFileUpload)
{
    int Fhz,Fhz1,Fhz2;
    string FilePath = asFileUpload.PostedFile.FileName.ToString();
    FileInfo myFileInfo = new FileInfo(FilePath);
    string PictureName = myFileInfo.Name.ToString();
    string FileExtends = null;
    if (PictureName != null)
    {
        FileExtends = GetFileExtends(PictureName);
        string BigPictureName = System.DateTime.Now.DayOfYear.ToString() + asFileUpload.PostedFile.ContentLength.ToString() + "." + FileExtends.ToString();
        string SmallPictureName = "S_" + BigPictureName.ToString();
        string BigPicturePath = asFilePath + BigPictureName.ToString();
        string SmallPicturePath = asFilePath + SmallPictureName.ToString();
        Fhz1 = PictureUpload(BigPicturePath, asFileUpload, FileExtends);
        Fhz2 = Miniature(FilePath, SmallPicturePath, 130, 130);
        Fhz = Fhz1 + Fhz2;
    }
    else
    {