I've reshuffled your query and everything appears to be working fine. I don't know where the error was coming from. Incidentally, if you're new to PHP then you may wish to read this article. It will help you get a better understanding of what types of variables you are dealing with.
$query = sprintf(" INSERT INTO images SET realname = '%s', user = '%s', size = %d, used = '%s', type = '%s', desc = '%s', ip = '%s', private = %d, report = %d", $filename_orig, $username, $filesize, $date, $filetype, $desc, $_SERVER['REMOTE_ADDR'], 1, 0);
The man who comes back through the Door in the Wall will never be quite the same as the man who went out.