Change upload file permissions to 664

I am having a funny problems with thumbnails which I have tracked down to permissions. I need uploaded images to have permissions of 664. How do you use chmod with the following code?

<?php
WA_DFP_SetupUploadStatusStruct("WA_UploadResult1");
if($_SERVER["REQUEST_METHOD"] == "POST"){
WA_DFP_UploadFiles("WA_UploadResult1", "itemImage", "2", "[ExistingFileName]_[Increment]", "PNG:9", $WA_UploadResult1_Params);
}
?>

I inserted chmod in the following way to get permissions to work:

WA_DFP_SetupUploadStatusStruct("WA_UploadResult1");
if($_SERVER["REQUEST_METHOD"] == "POST"){
chmod(WA_DFP_UploadFiles("WA_UploadResult1", "itemImage", "2", "[ExistingFileName]_[Increment]", "PNG:9", $WA_UploadResult1_Params), 664);
}

Issue is resolved.