Display Image in Image Control while Uploading Image Using FileUpload Control

Source File Code:
<script type="text/javascript">
function UploadImage()
{
document.getElementById('<%=BtnTemp.ClientID %>').click();
}
</script>
<asp:Image ID="Image1" runat="server" Height="97px" Width="130px" />
<asp:FileUpload ID="FileUpload1" OnChange="return UploadImage();" runat="server"
/> <div id="hide" style="display:none">
<asp:Button ID="BtnTemp" runat="server" OnClick="BtnTemp_Click" />
</div>
.Cs file Code:
protected void BtnTemp_Click(object sender, EventArgs e)
{
string FileName = FileUpload1.FileName;
string GudID = Guid.NewGuid().ToString();
string fullname = GudID +"_"+ FileName;
FileUpload1.SaveAs(Server.MapPath("~/Images/" + fullname));
Image1.ImageUrl = "~/Images/" + fullname;
}