ASP.net gridview cant update image - asp.net

Question

So i'm a newbie in asp.net. I have this college project which need to use update function. I made the update function, its work fine for all columns except for picture's column. Its not updating picture database, and show the previous picture in the gridview. The pictures in the folder already updated but the gridview just show the previous picture (not the updated one). I need your help please thank you :)
this is the gridview aspx code, if update button was clicked, it will redirect to another page.
<div>
<asp:Label ID="Label1" runat="server" Text=""></asp:Label>
<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="false">
<Columns>
<asp:TemplateField HeaderText="Images" ItemStyle-Height="50px" ItemStyle-Width="50px" >
<ItemTemplate>
<asp:Image ID="Image1" runat="server" ImageUrl='<%# Eval("pic") %>'/>/>
</ItemTemplate>
</asp:TemplateField>
<asp:BoundField DataField="nama" HeaderText="nama" />
<asp:BoundField DataField="harga" HeaderText="harga" />
<asp:BoundField DataField="stok" HeaderText="stok" />
<asp:TemplateField>
<ItemTemplate>
<asp:Button ID="btnUpdate" runat="server" OnClick="btnUpdate_Click" Text="Update" wID='<%# Eval("Id") %>'/>
</ItemTemplate>
</asp:TemplateField>
</Columns>
</asp:GridView>
</div>
this is the Page_Load function
public List<Table> getAll()
{
List<Table> watches = (from x in de.Tables select x).ToList();
return watches;
}
public void loadData()
{
GridView1.DataSource = repo.getAll();
GridView1.DataBind();
}
protected void Page_Load(object sender, EventArgs e)
{
if (!Page.IsPostBack) loadData();
}
and redirected to update aspx
<asp:Label ID="Label1" runat="server" Text="Label"></asp:Label>
<br />
<asp:FileUpload ID="pic" runat="server" />
<br />
<asp:TextBox ID="name" runat="server"></asp:TextBox>
<br />
<asp:TextBox ID="price" runat="server"></asp:TextBox>
<br />
<asp:TextBox ID="stok" runat="server"></asp:TextBox>
<br />
<asp:Button ID="btnUpdate" runat="server" Text="Button" OnClick="btnUpdate_Click" />
This is the update function of btnUpdate in update aspx
protected void btnUpdate_Click(object sender, EventArgs e)
{
string ext = System.IO.Path.GetExtension(pic.FileName);
string nama = name.Text;
int harga = Int32.Parse(price.Text);
int stock = Int32.Parse(stok.Text);
Table update = (Table)Session["updateWatch"];
string pict = "..\\Pictures\\Watch Pictures\\" + update.Id + ext;
bool updateStatus = repo.update(update.Id, pict, nama, harga, stock);
if (updateStatus == false) Label1.Text = "fail";
else
{
string subPic = update.pic.Substring(3);
string path = Server.MapPath("~") + subPic;
string savepath = Server.MapPath("~/Pictures/Watch Pictures/");
System.IO.File.Delete(path);
pic.SaveAs(savepath + update.Id + ext);
Response.Redirect("WebForm1.aspx");
}
}
this is the update function in repository
public bool update(int id, string pic, string nama, int harga, int stok)
{
Table updateW = (from x in de.Tables where x.Id == id select x).FirstOrDefault();
updateW.pic = pic;
updateW.nama = nama;
updateW.harga = harga;
updateW.stok = stok;
de.SaveChanges();
if (updateW == null) return false;
return true;
}
this is the code for gridview datasource
public List<Table> getAll()
{
List<Table> watches = (from x in de.Tables select x).ToList();
return watches;
}