Clear Image URL in Image control using JavaScript and C# in ASP.Net

Hello Forum,

please how do I clear an image in asp.net image control ?

I have an image control like this:

<asp:Image ID="Image3" runat="server" Width="260px" Height="400px" />

a javacript that displays image when uploaded:

    <script type="text/javascript">
        function ImagePreview(input) {
            if (input.files && input.files[0]) {
                var reader = new FileReader();
                reader.onload = function (e) {
                    $('#<%=Image3.ClientID%>').prop('src', e.target.result)
                        .width(260)
                        .height(400);
                };
                reader.readAsDataURL(input.files[0]);
            }
        }
    </script>

I used 

Image3.dispose ();

But it is not working