<asp:UpdateProgress ID="updProgress" runat="server">
    <ProgressTemplate>
        
    </ProgressTemplate>
</asp:UpdateProgress>

 
1    [Themeable(true)]
2        public partial class ucUpdateProgress : System.Web.UI.UserControl
3        {
4            private string _imgskinid = "BigProgressLoading";
5            public string ImgSkinID
6            {
7                get { return _imgskinid; }
8                set { _imgskinid = value; }
9            }
10           private string _progresstext = "Loading...";
11           public string ProgressText
12           {
13               get { return _progresstext; }
14               set { _progresstext = value; }
15           }
16           private bool _visibletext = true;
17           public bool VisibleText
18           {
19               get { return _visibletext; }
20               set { _visibletext = value; }
21           }
22           private bool _visibleimg = true;
23           public bool VisibleImage
24           {
25               get { return _visibleimg; }
26               set { _visibleimg = value; }
27           }
28           protected void Page_Load(object sender, EventArgs e)
29           {
30               Image imgProgress = new Image();
31               imgProgress.SkinID = this.ImgSkinID;
32               imgProgress.Visible = this.VisibleImage;
33               
34               Literal ltProgressText = new Literal();
35               ltProgressText.Text = this.ProgressText;
36               ltProgressText.Visible = this.VisibleText;
37   
38               updProgress.Controls.Add(imgProgress);
39               updProgress.Controls.Add(ltProgressText);
40           }
41   
42           
43       }

 
<asp:Image SkinID="BigProgressLoading" ImageUrl="Images/progress_loading.gif" runat="server" />