I believe by copyrighted materials he means sigs such as: (Sorry ronnie, just using as an example, no offence intended, quite like the sig anyway :) ) But I agree with remote: Alot of images are done by "render" sites who provide these images free and allow them to be used. As well as this most if not all companies such as game manufactures say use of their images is ok as long as it is not for commercial gain. Seeing as these sigs aren't giving commercial benefits its ok to use.