(PHP 5 >= 5.5.0)
imagescale — Scale an image using the given new width and height
$image
   , int $new_width
   [, int $new_height = -1
   [, int $mode = IMG_BILINEAR_FIXED
  ]] )imagescale() scales an image using the given interpolation algorithm.
imageUna risorsa immagine, restituita da una delle funzioni di creazione immagine, come imagecreatetruecolor().
new_widthThe width to scale the image to.
new_heightThe height to scale the image to. If omitted or negative, the aspect ratio will be preserved.
You should always provide the height if using PHP 5.5.18 or earlier, or PHP 5.6.2 or earlier, as the aspect ratio calculation was incorrect.
mode
      One of IMG_NEAREST_NEIGHBOUR,
      IMG_BILINEAR_FIXED,
      IMG_BICUBIC,
      IMG_BICUBIC_FIXED or anything else (will use two
      pass).
     
   Return the scaled image resource on success o FALSE in caso di fallimento.
  
| Versione | Descrizione | 
|---|---|
| 5.5.19/5.6.3 | 
        The calculation of the height if new_height was
        negative or omitted was fixed; prior to these versions, the aspect
        ratio was not maintained correctly.
        |