Converting uploaded images to PNG with PHP script

I've got an upload button I've made in Flash th开发者_开发知识库at links to a PHP script and I was wondering if there was any way I could convert all the images to PNGs as the user uploads them? This is what I have so far, but it doesn't seem to be working for me, can anyone point me in the right direction?

<?php
    if (move_uploaded_file($_FILES['Filedata']['tmp_name'], 
          "Parts/userdata/" . $_FILES['Filedata']['name']))
    {
        switch ($_FILES['Filedata']['type']) {
            case ".jpg": case ".jpeg":
                $image = imagecreatefromjpeg($_FILES['Filedata']['name']);
                imagepng($image, $_FILES['Filedata'] . 'png');
                imagedestroy($image);
                break;
            case "gif":
                $image = imagecreatefromgif($_FILES['Filedata']['name']);
                imagepng($image, $_FILES['Filedata'] . 'png');
                imagedestroy($image);
                break;
            default:
               echo "PNG Given";
        }
        echo "OK";
    }
    else
    {
         echo "ERROR";
    }
?>

Looking at some of my code, I think that

imagepng($image, $_FILES['Filedata'] . 'png');

should read

imagepng($image, $_FILES['Filedata']['name'] . 'png');

Or something similar. You probably want to remove the extension using basename or something similar. (http://php.net/manual/en/function.basename.php)