I didn't find a good method for that, as I didn't want to interfer with the normal post/editing. So I didn't feel like adding an error() page, and the only option would then be to make some kind of message transfer to pop up on the redirect page or something, and that just felt too complex to be simple ... and javascript is an option, that I don't like, so I ended up not adding that functionality ...
But you could probably add error messages in the attach.php file (in the include folder), I might even have the ifstatements ready for that (was a while since I peaked in my code), so you just need to add
error("some text");
(Edit: I think the browser is supposed to tell if you're trying to upload larger files than allowed in the MAXSIZE hidden variable, that normal member gets)
)
