Well, you all agreed to that at the registration:
You also agree not to post any copyrighted material unless you own the copyright or you have written consent from the owner of the copyrighted material. Spam, flooding, advertisements, chain letters, pyramid schemes, and solicitations are also forbidden on this forum.
Note that it is impossible for the staff or the owners of this forum to confirm the validity of posts. Please remember that we do not actively monitor the posted messages, and as such, are not responsible for the content contained within.
and to this:
You remain solely responsible for the content of your posted messages.
I am not a lawyer but I think this does include attachments, too.
It should be enough if
you don't have a knowledge that some materials were posted without owner's permission. Also, you don't have to check content posted by other forum members. But if
you know that someone has posted copyrighted material without author's permission, you should rather remove it. Of course, the risk that someone will sue you for allowing to post and store illegal content is extremely small, but for some people it can be simply unacceptable and have bad impact on the popularity of this forum (and of course EGSL an NaaLaa, too). So, if someone wants to use someone else's work without permission, he/she should take full responsibility for it by not informing about it on the forum. Just my opinion.