Image upload question

Hi all,

I've got an image upload section for an admin page.  I've tried countless tutorials, but I just can't seem to get anything to work the way I want it to.  I'm trying to resize the uploaded image to a specific size (w=215; h=250) and maintain the transparency of the png file.  All I can get to work is a simple upload that does not resize.  So far I've got this:

$current_image=$_FILES['image']['name'];
$extension = substr(strrchr($current_image, '.'), 1);
if ($extension != "png")
{
die('Unknown extension');
}
$new_image = $current_image;
$destination="../../assets/subfolder/".$country."/".$new_image;
$action = copy($_FILES['image']['tmp_name'], $destination);
if (!$action) 
{
die('File copy failed');
}else{

Can anyone please help me get this to resize and keep the transparency?  Or point me in the right direction where I can find a tutorial that I can get to work?

Thank you very much.,