uploading the image and displaying but next time not displaying the image

3. Modify your button_click like below
protected void Button1_Click(object sender, EventArgs e)
{
//Label1.Text = "Hello Click Here";
string fn = FileUpload1.PostedFile.FileName;
string[] fi = fn.Split('\\');
string name = fi[fi.Length - 1];
FileUpload1.PostedFile.SaveAs(Server.MapPath("images/" + name));
Old.ImageUrl = New.ImageUrl;
Session["OldImage"] = Old.ImageUrl;
New.ImageUrl = "~/images/" + FileUpload1.FileName;
Session["NewImage"] = New.ImageUrl;
}
4. In Page_Load write below llines
if (!IsPostBack)
{
New.ImageUrl = GetNewImage();
Old.ImageUrl = GetOldImage();
}