allocation memoire - hebergement ?

function vignette($img, $img_dest, $width=0, $height=0)
{
  $size = GetImageSize($img);
  $src_w = $size[0];
  $src_h = $size[1];

  if($width != 0 | $height != 0)
  {
    if($src_w > $width | $src_h > $height)
    {
      if($src_w > $src_h && $width != 0)
      {
        //On retrecit la largeur
        $height = ceil(($src_h / $src_w) * $width);
      }
      elseif($src_h > $src_w && $height != 0)
      {
        //On retrecit la hauteur
        $width = ceil(($src_w / $src_h) * $height);
      }
    }
    else
    {
      $width = $src_w;
      $height = $src_h;
    }    
  }
  else
  {
    $width = $src_w;
    $height = $src_h;    
  }
  $ext = explode(".", $img);
  $ext = $ext['1'];
  $dst_im = ImageCreateTrueColor($width,$height);
  $trans_color = imagecolorallocate($dst_im, 255, 0, 0);
  if(!$dst_im)
  {
    return 0;
  }       
  if($ext == 'jpg' or $ext == 'jpeg' or $ext == 'JPG' or $ext == 'JPEG')
  {
    $src_im = ImageCreateFromJpeg($img);
  }
  elseif($ext == 'gif')
  {
    $src_im = imagecolortransparent($dst_im, $trans_color);
    $src_im = ImageCreateFromGif($img);
  }
  elseif($ext == 'png')
  {
    $src_im = ImageCreateFromPng($img);
  }
  else
  {
    return 0;
  }
  if (!$src_im)
  {
    return 0;
  }

  ImageCopyResampled($dst_im,$src_im,0,0,0,0,$width,$height,$src_w,$src_h);

  if($ext == 'jpg' or $ext == 'jpeg' or $ext == 'JPG' or $ext == 'JPEG')
  {
    ImageJpeg($dst_im,$img_dest);
  }
  elseif($ext == 'gif')
  {
    ImageGif($dst_im,$img_dest);
  }
  elseif($ext == 'png')
  {
    ImagePng($dst_im,$img_dest);
  }
  else
  {
    return 0;
  }
          
  ImageDestroy($dst_im);
  return 1;
}

$src_im = ImageCreateFromJpeg($img);