[PROBLEMA]Immagini rinominare numericamente a caso e link pdf

[clasku]

function upload_image(){
 if(isset($_FILES["user_image"])) {
   // $extension = explode('.', $_FILES['user_image']['name']);
   // $new_name = rand() . '.' . $extension[1];
   // $destination = './upload/' . $new_name;
   $destination = './upload/' . $_FILES['user_image']['name'];
   move_uploaded_file($_FILES['user_image']['tmp_name'], $destination);
   //return $new_name;
   return $_FILES['user_image']['name'];
 }
} 

prova così, ho cambiato il valore del return nella funzione