How to change the file upload directory on version 3.5?

In addition to what Joseph suggested, you can also define the upload path in the wp-config.php file like this:

define( 'UPLOADS', 'wp-content/'.'files' );

If you’d like it outside the wp-content folder, specify path like this:

define( 'UPLOADS', ''.'uploads' );

For uploading to a folder like example.com/images, use this code:

//Custom upload path
define( 'UPLOADS', ''.'images' );