for file upload to function properly, the forms encoding type must be set to multipart/form-data.
change the form tag:
<form action="Contact_Update.php?Contact_ID=<?php echo(rawurlencode($row_WADAtbl_Contact['Contact_ID'])); ?>" method="post" name="WADAUpdateForm" id="WADAUpdateForm">
to:
<form action="Contact_Update.php?Contact_ID=<?php echo(rawurlencode($row_WADAtbl_Contact['Contact_ID'])); ?>" method="post" enctype="multipart/form-data" name="WADAUpdateForm" id="WADAUpdateForm">