ckeditor image upload php backend

upload.php

<?php

//ck editor config
//config.extraPlugins = 'uploadimage';
//config.imageUploadUrl='/upload/upload.php';

$maxSizeInMo=50;
$csrfName = "ckCsrfToken";
$token = $_POST[$csrfName];
$uploadKey = "upload";
$targetDir = "data/";

//Security check
if($token == $_COOKIE[$csrfName] && isset($_FILES[$uploadKey]))
{

    $tmpPath   = $_FILES[$uploadKey]["tmp_name"];

    //Format check
    if(getimagesize($tmpPath)!==false)
    {

        $tmpName = basename($tmpPath);
        $nameWithExtension  = basename($_FILES[$uploadKey]["name"]);
        //$extension = strtolower(pathinfo($nameWithExtension,PATHINFO_EXTENSION));

        $targetName = $tmpName . "-" .$nameWithExtension;

        $targetPath = dirname(__FILE__) . "/" . $targetDir . $targetName;

        // Check file size
        if ($_FILES[$uploadKey]["size"] > (1024*1024*$maxSizeInMo))
        {
            error("Sorry, your file is too large (max=".$maxSizeInMo .")");
        }
        //Should never happen (tmp_name is unique)
        else if(file_exists($targetPath))
        {
            error("Sorry, file already exists.");
        }
        else
        {
            $targetType = $_FILES[$uploadKey]["type"];
            //

            // Allow certain file formats
            if($targetType != "image/jpg" && $targetType != "image/png" && $targetType != "image/jpeg" && $targetType != "image/gif" && $targetType != "image/bmp" )
            {
                error("Sorry, only JPG, JPEG, PNG & GIF & BMP files are allowed.");
            }
            else
            {
                if (move_uploaded_file($tmpPath, $targetPath)) {
                    //echo "The file ". htmlspecialchars($targetPath). " has been uploaded.";

                    $url = "/" . basename(dirname(__FILE__)) . "/" . $targetDir . $targetName;

                    $json["uploaded"] = true;
                    $json["url"] = $url;
                    echo json_encode($json);

                } else {
                    error("Sorry, there was an error uploading your file.");
                }
            }
        }
    }
}

function error($message)
{
    $json["uploaded"] = false;
    $json["error"] = array("message" => $message);
    echo json_encode($json);
}