for file upload to work, the forms encoding type must be set to multipart/form-data. change the form tag to:
<form action="tblNews_Update.php?intNewID=<?php echo(rawurlencode($row_WADAtblNews['intNewID'])); ?>" method="post" enctype="multipart/form-data" name="WADAUpdateForm" id="WADAUpdateForm">
for the update page to function properly, you need to create a hidden form element, set the value of the hidden form element to use the value that is in the recordset.
in the uplaod file behavior, set the default value option to use the hidden form element.
this is covered in detail in the "Applying File Upload to DataAssist Insert and Update pages" how to on the universal email support page: