PHP Add text to image and save - php

Question

I am attempting to have a PHP file add an ID to an uploaded image and resave the image. For some reason the code below is not working even though it looks very similar to other examples I have found online. What am I doing wrong?
$productStyle = isset($_POST['productStyle']) ? encodechars($_POST['productStyle']) : "";
$productSize = isset($_POST['productSize']) ? encodechars($_POST['productSize']) : "";
$itemID = isset($_POST['itemID']) ? encodechars($_POST['itemID']) : "";
if ($productStyle!=""){
$fileLocation ='/home/abcdefg/public_html/uploads/'.$productStyle;
$photoLoc = $fileLocation . "/" . $itemID.".png";
if(!is_dir($fileLocation)) {
mkdir($fileLocation , 0777); //create directory if it doesn't exist
}
//add id to image
$im = imagecreatefrompng($_FILES["file"]["tmp_name"]);
$font = 'Verdana.ttf'; //<-- this file is included in directory
$grey = imagecolorallocate($im, 128, 128, 128);
imagettftext($im, 10, 0, 11, 20, $grey, $font, $itemID);
imagepng($im, $photoLoc); //<-- This does not work
imagedestroy($im);
//move_uploaded_file($_FILES["file"]["tmp_name"], $photoLoc); //<-- This will move the file to the correct folder but without the text added
}

Answer 1

first, move the original file and then remove after watermarking.
$productStyle = isset($_POST['productStyle']) ? encodechars($_POST['productStyle']) : "";
$productSize = isset($_POST['productSize']) ? encodechars($_POST['productSize']) : "";
$itemID = isset($_POST['itemID']) ? encodechars($_POST['itemID']) : "";
if ($productStyle!=""){
$fileLocation ='/home/abcdefg/public_html/uploads/'.$productStyle;
$photoLoc = $fileLocation . "/" . $_FILES["file"]["name"];
move_uploaded_file($_FILES["file"]["tmp_name"], $_FILES["file"]["name"]);
if(!is_dir($fileLocation)) {
mkdir($fileLocation , 0777); //create directory if it doesn't exist
}
//add id to image
$im = imagecreatefrompng($photoLoc);
$font = 'Verdana.ttf'; //<-- this file is included in directory
$grey = imagecolorallocate($im, 128, 128, 128);
imagettftext($im, 10, 0, 11, 20, $grey, $font, $itemID);
imagepng($im, $photoLoc); //<-- This does not work
imagedestroy($im);
unlink($photoLoc);
//move_uploaded_file($_FILES["file"]["tmp_name"], $photoLoc); //<-- This will move the file to the correct folder but without the text added
}
or just change
$im = imagecreatefrompng($_FILES["file"]["tmp_name"]);
to
$im = imagecreatefrompng($_FILES["file"]["name"]);