I may have misunderstood the question. In order to make it not overwrite the database when no value has been entered into the file upload you can use the "Default File" setting from the file upload server behavior and set it to the existing file from the recordset.
It would effect this line:
'DefaultFileName' => "",
Changing it to:
'DefaultFileName' => "". $Recordset1->getColumnVal('tip_photo') ."",