PHP - move_uploaded_file无法在Windows服务器上运行，即使IS_USRS具有权限

I have added IS_USRS full permissions to my /courseimages/ folder, but I still cant upload the file:

$feedback = "&img".$index."=$img";
echo "<p>img: $img</p>";
echo "<p>tmp_name: $tmp_name</p>";
echo "<p>PHP User: ".exec('whoami')."</p>";
if ( ! is_writeable ( "../courseimages/$img" ) )
{
    echo "<p>Can't write to directory, insufficient permissions.</p>";
}
if(move_uploaded_file($tmp_name, "../courseimages/$img")){
    $feedback .="&moved=true";
}else{
    $feedback .="&moved=false";
}
echo $feedback;
resize_image("../courseimages/$img", "../courseimages/$img");

Produces:

img: 212_1862_6918_Rambow_Corgi.jpg

tmp_name: C:\Windows\Temp\php411.tmp

PHP User: nt authority\iusr

Can't write to directory, insufficient permissions.

&img1=212_1862_6918_Rambow_Corgi.jpg&moved=falseUpload: Rambow Corgi.jpg

BUT Permissions are set:

enter image description here

I have read many articles, tried many things, I cant figure it out - thanks in advance