access denied while uploading images online webapplication

You should provide your code and explain more about your problem.
ok, I can guess that you are talking about image path of ASP.NET Client side. you cant find full path of any uploaded document. So you can encode your uploaded image on client side and also can view the image, after postback on button click get the encode (base64) data to binary and save to database or store image on application server.

follow this given code:

<form id="form1" runat="server">
    <div>
        <asp:Image ID="imgEmployee"  runat="server" ImageUrl="" Width="100px"
                    Height="120px" />

        <script type="text/javascript">
            function handleFileSelect(evt) {

                var fileUpload = document.getElementById('<%=photoUpload.ClientID%>');
                var imgEmployee = document.getElementById('<%=imgEmployee.ClientID%>');

                var files = evt.target.files; // FileList object
                // Loop through the FileList and render image files as thumbnails.
                for (var i = 0, f; f = files[i]; i++) {

                    // Only process image files.
                    if (!f.type.match('image.*')) {
                        continue;
                    }
                    var reader = new FileReader();
                    var base64Data;

                    reader.onload = (function (theFile) {
                        return function (e) {
                            // Render thumbnail.
                            var span = document.createElement('span');

                            base64Data = e.target.result;
                            var fileSize = base64Data.length;
                            var IndexData = base64Data.indexOf('base64,');
                            var fileName = escape(theFile.name);
                            imgEmployee.src = base64Data;


                        };
                    })(f);
                    // Read in the image file as a data URL.
                    reader.readAsDataURL(f);
                }
            }





        </script>
        <div>

<asp:FileUpload runat="server" ID="photoUpload" TabIndex="7"  onchange="handleFileSelect(event)"   />


        </div>

    </div>
    </form>