I thought as long as someone isn't profiteering, then your free to use whatever. If there is no personal, social or other gain then surely that can't be copyright. With things like pictures if there is an infringement then all they can do is ask that it is removed. They cannot do anything more until they have shown all reasonable efforts to get the offender to desist.
And the letter would be a cease and desist order.
plus as you say there is no copyright notice on the pictures