I use this script for uploading an image file. It should allow to upload jpeg, jpg and png files.
Everything works on remote server, but I can't upload it locally, on XAMPP server. I tried all tips mentioned in this thread Why would $_FILES be empty when uploading files to PHP? but no one worked.
Thanks for help
Form:
<form class="form-horizontal" action="potwierdz.php" method="POST" enctype="multipart/form-data">
    <fieldset>
        <!-- Form Name -->
        <legend>Dodawanie produktu</legend>
        <!-- Text input-->
        <div class="form-group">
          <label class="col-md-4 control-label" for="produkt_nazwa">Nazwa</label>  
          <div class="col-md-4">
              <input id="produkt_nazwa" name="produkt_nazwa" class="form-control input-md" required="" type="text">
              <span class="help-block">Podaj nazwę produktu</span>  
          </div>
        </div>
        <!-- Text input-->
        <div class="form-group">
          <label class="col-md-4 control-label" for="producent_nazwa">Nazwa producenta</label>  
          <div class="col-md-4">
              <input id="producent_nazwa" name="producent_nazwa" class="form-control input-md" required="" type="text">
              <span class="help-block">Podaj nazwę producenta produktu</span>  
          </div>
        </div>
        <!-- Textarea -->
        <div class="form-group">
          <label class="col-md-4 control-label" for="producent_adres">Adres producenta</label>
          <div class="col-md-4">                     
            <textarea class="form-control" id="producent_adres" name="producent_adres" required=""></textarea>
          </div>
        </div>
        <!-- Select Basic -->
        <div class="form-group">
          <label class="col-md-4 control-label" for="produkt_kategoria_nazwa">Kategoria</label>
          <div class="col-md-4">
            <select id="produkt_kategoria_nazwa" name="produkt_kategoria_nazwa" class="form-control">
                <option> </option>
            </select>
          </div>
        </div>
        <!-- File Button --> 
        <div class="form-group">
          <label class="col-md-4 control-label" for="obraz">Zdjęcie</label>
          <div class="col-md-4">
            <input id="obraz" name="obraz" class="input-file" type="file">
          </div>
        </div>
        <!-- Button -->
        <div class="form-group">
          <label class="col-md-4 control-label" for="wyslij"></label>
          <div class="col-md-4">
            <button id="wyslij" name="wyslij" class="btn btn-primary">Dodaj</button>
          </div>
        </div>
    </fieldset>
</form>
here is script:
<?php
    $errors= array();
      $file_name = $_FILES['obraz']['name'];
      $file_size =$_FILES['obraz']['size'];
      $file_tmp =$_FILES['obraz']['tmp_name'];
      $file_type=$_FILES['obraz']['type'];
      $file_ext=strtolower(end(explode('.',$_FILES['obraz']['name'])));
      $expensions= array("jpeg","jpg","png");
      if(in_array($file_ext,$expensions)=== false){
         $errors[]="extension not allowed, please choose a JPEG or PNG file.";
      }
      if(empty($errors)==true){
         move_uploaded_file($file_tmp,"obrazki/".$file_name);
         echo "Success";
      }else{
         print_r($errors);
      }
?>
It returns me "extension not allowed, please choose a JPEG or PNG file."
It's also printing 
Notice: Undefined index: obraz
whenever I use $_FILES['obraz']['...'] variable.