uploading animated image

Question is quite unclear but i guess you are talking about uploading Animated GIF files..

You can use asp:fileupload control and can put validation for preventing other file formats than GIF...

<asp:FileUpload id="FileUploadControl" runat="server" />
<asp:Button runat="server" id="UploadButton" text="Upload" onclick="UploadButton_Click" />

protected void UploadButton_Click(object sender, EventArgs e)
{
    if(FileUploadControl.HasFile)
    {
        try
        {
            string filename = Path.GetFileName(FileUploadControl.FileName);
            FileUploadControl.SaveAs(Server.MapPath("~/") + filename);
            StatusLabel.Text = "Upload status: File uploaded!";
        }
        catch(Exception ex)
        {
            StatusLabel.Text = "Upload status: The file could not be uploaded. The following error occured: " + ex.Message;
        }
    }
}

Hope this will help..