Ciao a tutti,

ho una funzione scritta in php che viene richiamata (a quanto pare) anche quando non dovrebbe essere richiamata.

vi incollo tutta la pagina php così avete una visione completa

codice:
<?phpsession_start();
/* FUNCTION COMPRESS IMAGE */
function compress_image($source_url,$destination_url,$quality) {
  $info = getimagesize($source_url);
  if($info['mime'] == 'image/jpeg') {
    $image = imagecreatefromjpeg($source_url);
  }
  elseif($info['mime'] == 'image/png') {
    $image = imagecreatefrompng($source_url);
  }
  imagejpeg($image,$destination_url,$quality);
  return $destination_url;
}
/* IMAGE RESIZE LIBRARY */
include_once 'ImageResize.php';
use \Eventviva\ImageResize;
include_once 'config.php';
// PRENDO INFO NEWS 
if(isset($_GET['news'])) {
  $sel_news = $db->prepare("SELECT * FROM mbe_news WHERE id=:id");
  $sel_news->execute(array(':id'=>$_GET['news']));
  $res_news = $sel_news->fetch();
  $titolo = $res_news[2];
  $descrizione = $res_news[3];
  $sorgente = $res_news[4];
  // MODIFICA GALLERY
  if(isset($_POST['submitModNews']) and $_SERVER['REQUEST_METHOD'] == "POST") {
    $mod_news = $db->prepare("UPDATE mbe_news SET titolo=:titolo, descrizione=:descrizione WHERE id=:id");
    $mod_news->execute(array(':titolo'=>$_POST['inputModTitle'],':descrizione'=>$_POST['inputModTesto'],':id'=>$_GET['news']));
    // aggiungi immagini a gallery esistente
    $cartella_news = "img/news/".$_GET['news'];
    if(!empty($_FILES["mod_gallery_news"])) {
      $num_files = count($_FILES["mod_gallery_news"]["tmp_name"]);
      for($i=0;$i<$num_files;$i++) {
        compress_image($_FILES["mod_gallery_news"]["tmp_name"][$i],$cartella_news."/".$_FILES["mod_gallery_news"]["name"][$i],90);
      }
      $resize_files = glob($cartella_news."/*.*");
      for($i=0;$i<count($resize_files);$i++) {
        $image = $resize_files[$i];
        $supported_file = array('jpg','jpeg','png','JPG','PNG','JPEG');
        $ext = strtolower(pathinfo($image, PATHINFO_EXTENSION));
        if(in_array($ext, $supported_file)) {
          $resize = new ImageResize($image);
          $resize->resizeToHeight(500);
          $resize->save($image);
        }
        else {
          continue;
        }
      }
    }
    header("Location:list_news_admin.php");
  }
}
?>
<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="utf-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <title>MBE - Admin</title>
    <!-- FAVICON -->
    <link rel="shortcut icon" href="img/favicon.ico" type="image/x-icon">
    <link rel="icon" href="img/favicon.ico" type="image/x-icon">
    <!-- /FAVICON -->
    <link href="http://cdnjs.cloudflare.com/ajax/libs/font-awesome/4.3.0/css/font-awesome.min.css" rel="stylesheet" type="text/css">
    <link href="css/pingendo-bootstrap.css" rel="stylesheet" type="text/css">
    <link href="//netdna.bootstrapcdn.com/bootstrap/3.0.0/css/bootstrap-glyphicons.css" rel="stylesheet">
    <link href="css/bootstrap-toggle.min.css" rel="stylesheet">
    <!-- Custom styles for this template -->
    <link href="css/style.css" rel="stylesheet">
    <!-- Just for debugging purposes. Don't actually copy this line! -->
    <!--[if lt IE 9]><script src="../../assets/js/ie8-responsive-file-warning.js"></script><![endif]-->
    <!-- HTML5 shim and Respond.js IE8 support of HTML5 elements and media queries -->
    <!--[if lt IE 9]>
      <script src="https://oss.maxcdn.com/libs/html5shiv/3.7.0/html5shiv.js"></script>
      <script src="https://oss.maxcdn.com/libs/respond.js/1.4.2/respond.min.js"></script>
    <![endif]-->
  </head>
  <body>
  <?php
  if(!isset($_SESSION['admin'])) {
  ?>
    <div class="section dark">
      <div class="container">
        <div class="row">
          <div class="col-md-12 col-sm-12 col-xs-12 text-center">
            <h1 class="title">Pannello di controllo&nbsp;&nbsp;<i class="fa fa-cog fa-spin"></i></h1>
          </div>
          <div class="col-md-6 col-md-offset-3 col-sm-8 col-sm-offset-1 col-xs-12 text-center">
            <form class="margined-top" method="POST" action="login.php">
              <div class="form-group col-md-12 col-sm-12 col-xs-12">
                <label class="label-light" for="inputAdmin">Username</label>
                <input type="text" class="form-control" id="inputAdmin" name="inputAdmin">
              </div>
              <div class="form-group col-md-12 col-sm-12 col-xs-12">
                <label class="label-light" for="inputPassword">Password</label>
                <input type="password" class="form-control" id="inputPassword" name="inputPassword">
              </div>
              <div class="form-group col-md-12 col-sm-12 col-xs-12 text-center">
                <a href="index.php" class="btn btn-lg btn-primary">Torna al sito</a>
                <button type="submit" class="btn btn-lg btn-success" name="submitAdmin">Accedi</button>
              </div>
            </form>
          </div>
        </div>
      </div>
    </div>
  <?php
  }
  else {
  ?>
    <div class="section dark">
      <div class="container">
        <div class="row">
          <div class="col-md-12 col-sm-12 col-xs-12 text-center">
            <h1 class="title">Benvenuto Amministratore</h1>
            <h2 class="subtitle">Modifica News</h2>
          </div>
          <div class="col-md-12 col-sm-12 col-xs-12 text-center margined-top">
            <div class="col-md-4 col-sm-4 col-xs-12">
              <a href="index.php" class="btn btn-lg btn-block btn-primary"><i class="fa fa-home"></i>&nbsp;&nbsp;Home</a>
            </div>
            <div class="col-md-4 col-sm-4 col-xs-12">
              <a href="admin.php" class="btn btn-lg btn-block btn-warning"><i class="fa fa-wrench"></i>&nbsp;&nbsp;Pannello</a>
            </div>
            <div class="col-md-4 col-sm-4 col-xs-12">
              <a href="logout.php" class="btn btn-lg btn-block btn-danger"><i class="fa fa-times"></i>&nbsp;&nbsp;Esci</a>
            </div>
          </div>
        </div>
      </div>
    </div>
    <div class="section light">
      <div class="container">
        <div class="row">
          <div class="col-md-12 col-sm-12 col-xs-12">
            <a href="list_news_admin.php" class="btn btn-custom-black btn-lg"><i class="fa fa-chevron-left"></i>&nbsp;&nbsp;Indietro</a>
          </div>
          <form method="POST" action="modify-news.php?news=<?php echo $_GET['news'];?>" enctype="multipart/form-data">
            <div class="col-md-6 col-sm-6 col-xs-12 text-left">
              <?php
              $files = glob($sorgente."/*.*");
              for($i=0;$i<count($files);$i++) {
                $image = $files[$i];
                $supported_file = array('jpg','jpeg','png');
                $ext = strtolower(pathinfo($image, PATHINFO_EXTENSION));
                if(in_array($ext, $supported_file)) {
                ?>
                <div class="col-md-4 col-sm-4 col-xs-12 margined-top">
                  <img src="<?php echo $image;?>" alt="<?php echo $titolo;?>" style="width:100%;height:auto;">
                  <a href="delete-img.php?image=<?php echo $image;?>" class="btn btn-danger btn-block"><i class="fa fa-trash-o"></i>&nbsp;&nbsp;Elimina</a>
                </div>
                <?php
                }
              }
              ?>
            </div>
            <div class="col-md-6 col-sm-6 col-xs-12 text-center margined-top">
              <div class="form-group">
                <input type="text" name="inputModTitle" class="form-control" value="<?php echo $titolo;?>">
              </div>
              <div class="form-group">
                <textarea rows="10" name="inputModTesto" class="form-control"><?php echo $descrizione;?></textarea>
              </div>
              <div class="form-group">
                <input type="file" name="mod_gallery_news[]" id="galleryImages" multiple="multiple" class="form-control" accept="image/*">
              </div>
            </div>
            <div class="col-md-12 col-sm-12 col-xs-12 text-right margined-top">
              <button type="reset" class="btn btn-lg btn-danger">Annulla&nbsp;&nbsp;<i class="fa fa-times"></i></button>
              <button type="submit" class="btn btn-lg btn-success" name="submitModNews">Modifica&nbsp;&nbsp;<i class="fa fa-pencil"></i></button>
            </div>
          </form>
        </div>
      </div>
    </div>
  <?php
  }
  ?>
    <script src="//cdn.ckeditor.com/4.5.6/basic/ckeditor.js"></script>
    <script type="text/javascript" src="http://cdnjs.cloudflare.com/ajax/libs/jquery/2.0.3/jquery.min.js"></script>
    <script type="text/javascript" src="http://netdna.bootstrapcdn.com/bootstrap/3.3.4/js/bootstrap.min.js"></script>
    <script>
    CKEDITOR.replace('inputModTesto');
    </script>
  </body>
</html>

COSA SUCCEDE?

se io modifico ad esempio il titolo della news, e lascio vuoto il campo $_FILES quindi l'input file e premo il submit la pagina mi restituisce questi errori:

Notice: Undefined variable: info in /home/mbe026/public_html/modify-news.php on line 8

Notice: Undefined variable: info in /home/mbe026/public_html/modify-news.php on line 11

Notice: Undefined variable: image in /home/mbe026/public_html/modify-news.php on line 14

Warning: imagejpeg() expects parameter 1 to be resource, null given in /home/mbe026/public_html/modify-news.php on line 14

Warning: Cannot modify header information - headers already sent by (output started at /home/mbe026/public_html/modify-news.php:8) in /home/mbe026/public_html/modify-news.php on line 55