如何解决图片上传问题

Question

I'm using Google cloud storage for hosting my website, i have code to upload the cover image like Facebook once user select the image it will upload to the server and same time it will fetch the image.

i gave full access to only that cover image folder, if i gave like that any problem will come like hacking. Please give me an advice my ways good or not?

if (!is_dir($directoryName)) {
                $oldmask = umask(0);
                mkdir($directoryName, 0777);
                umask($oldmask);
            }