上传文件
 try
{
string proimg = Utility.Tool.Upload(fuimg, new string[] { ".jpg",".png",".gif",".bmp" }, 1, Server.MapPath("/upload/"));  
imgYL.ImageUrl = "/upload/" + proimg;
imgYL.ToolTip = proimg;
}
catch (Exception ex)
{
Utility.Tool.ExecJs(ex.Message, this.Page);
}

上传并生成缩略图
protected void Upload(object sender, EventArgs e)
{
try
{
string filename = Utility.Tool.Upload(fu, new string[] { ".jpg" }, 4, Server.MapPath("../upload/"));//上传
#region 生成120*120大小的图像
//filename = "20120123/67be9372-3242-4653-b5ad-195ac9d1edb3.jpg";
//目标图像 ＝ "20120123/big_67be9372-3242-4653-b5ad-195ac9d1edb3.jpg";
string[] ss = filename.Split('/');//用"/"分割
string tpath = Server.MapPath("../upload/" + ss[0] + "/big_" + ss[1]);//新的地址及名称big_
Utility.Tool.CreateImage(Server.MapPath("../upload/" + filename), tpath, 120, 120);//生成缩略图
#endregion
#region 生成48*48大小的图像
tpath = Server.MapPath("../upload/" + ss[0] + "/small_" + ss[1]);//生成新图:small_
Utility.Tool.CreateImage(Server.MapPath("../upload/" + filename), tpath, 48, 48);
#endregion

System.IO.File.Delete(Server.MapPath("../upload/" + filename));//删除原图
filename = ss[0] + "/big_" + ss[1];//新的名称保存到数据库中的

Model.User u = Session["user"] as Model.User;//通过session读取model
u.face = filename;
new DAL.UserDAL().Update(u);//更新
Utility.Tool.AlertAndGo("头像上传成功。",Request.Url.ToString(), this.Page);
}
catch (Exception ex)
{
Utility.Tool.Alert(ex.Message, this.Page);
}

}
前台读取
imgface.ImageUrl = root + "upload/" + u.face.Replace("big_", "small_");//把取出的头像big_替换成small_