Problema con le trasparenza

[skill83]

anche se inserisco

$immagine = date("dmyHis").".png";
$image_p = imagecreatetruecolor($finalsizew, $finalsizeh);  
$image   = imagecreatefrompng($file['tmp_name']);
imagealphablending($image, true); // setting alpha blending on
imagesavealpha($image, true);
imagecopyresampled($image_p, $image, 0, 0, 0, 0, $finalsizew, $finalsizeh, $width, $height);
imagepng($image_p, $file['tmp_name']);  
imagedestroy($image);
imageDestroy($image_p);
break; 

sempre nero