Once the Web server received the uploaded file, it will call the PHP
script specified in the form action attribute to process them. This
receiving PHP script can get the uploaded file information through the
predefined array called $_FILES. Uploaded file information is organized
in $_FILES as a two-dimensional array as:
$_FILES[$fieldName]['name'] - The Original file name on the browser
$_FILES[$fieldName]['type'] - The file type determined by the browser.
$_FILES[$fieldName]['size'] - The Number of bytes of the file content.
$_FILES[$fieldName]['tmp_name'] - The temporary filename of the file in
which the uploaded file was stored on the server.
$_FILES[$fieldName]['error'] - The error code associated with this file
The $fieldName is the name used in the <INPUT TYPE=FILE, NAME=fieldName>.