I think it is as long as you don't sell them.
You could be infringing on a copyright whether it's free or sold (I would look to the Terms of Use (TOU) of the Web site to see what the copyright owners allow one to do with the content. They may be less likely to sue for copyright infringement if they are giving it away for free, but I personally wouldn't want to take any chances (but, that's me and due also to employment obligations).