$_FILES['userfile']['name']
 
    The original name of the file on the client machine.  
$_FILES['userfile']['type']
 
    The mime type of the file, if the browser provided this information. An example would be "image/gif". This mime type is however not checked on the PHP side and therefore don't take its value for granted.  
$_FILES['userfile']['size']
 
    The size, in bytes, of the uploaded file.  
$_FILES['userfile']['tmp_name']
 
    The temporary filename of the file in which the uploaded file was stored on the server.  
$_FILES['userfile']['error']
 
    The error code associated with this file upload. This element was added in PHP 4.2.0