to trouble shot why the image is not uploading, make sure that the page does not redirect to another page. Then add the following at line 1:
<?php
error_reporting(E_ALL);
ini_set('display_errors','on');
?>
This will let us know if there is a php error occurring.
next, go to the bindings panel and expand the WA Uploaded Files Global group and drag the debug info binding to your page. now test an upload and post back the debug info and any php errors if the appear.