I'll post and explain the section from the AUP, because that's just part of it - the actual part (5.1) of the AUP which is most important has been left out of the discussion:
5.1 All third party files offered on our web sites remain the copyright of their respective holders. The postings made in the Forums remain the copyright of their respective author.
Anything you post or upload to TGC's website remain your copyright/ownership. Unless you specify who holds the copyright, it is assumed that it belongs to you.
5.2 By posting your messages / files and screen shots to our web sites you are giving us express permission to display and redistribute those files in any manner we see fit including all forms of digital and printed media.
Redistribute means those files can be moved to wherever they need to be, display means that you give permission for TGC to show your images wherever relevant. By posting a screenshot, you are also allowing TGC to show that same screenshot in a fairly lax way - it means they can show it in your thread, but also they might include it in the newsletter, or even printed media (magazine reviews of TGC products - using your images to show what can be done).
5.3 If you wish to post screen shots / files that are of work controlled under copyright and/or distribution restrictions then you must obtain permission from us before doing so, otherwise you forfeit this right. The content of all web sites, unless stated otherwise, is (C) Copyright The Game Creators Ltd, all rights reserved.
If you are held under any copyrights for what you are uploading, then that needs to be discussed with TGC so that the copyright agreement can be upheld - maybe it's fine for screenshots of a certain version of the software but not others, maybe the developer wants to keep things on the down low, so might only want the image to be displayed on the forum to registered members, but not the newsletter etc. Again, copyright/ownership is assumed because nobody really expresses that here in a legal sense - it would probably only be a factor if you were bound by an Non-Disclosure Agreement - but you wanted to say, upload a screenshot of a bug.
This bit:
The content of all web sites, unless stated otherwise, is (C) Copyright The Game Creators Ltd, all rights reserved.
That's a sentence, it pertains to the website your actually looking at - not your screenshots or anything like that. TGC take no ownership of your media, they assume permission to use it because you uploaded a screenshot to their website, that is pretty much all.
