I can understand the Forum Admins position given their relationship with GARF.
Personally however I think being precious about historical photos, and copywriting them, is absolute, total, complete BS! Like written texts, photos should not be able to be copyrighted after 50 years. (And as an aside, I think Helen R is being very silly about that photo if she objects to it going online now. It's great PR for her book.)
As an example of the way things are headed, Getty Images have opened up their holdings to linking in the last few weeks.
The Romanov photo albums at Yale have been freely available to all online for years. GARF need to pull their fingers out and make their holdings equally accessible. And even then I doubt they'd serve them up in the wonderful ultra high res versions we've been treated to here.
That said, things aren't going to change over night. So I think it's excellent advice that 'problematic' photos are not embedded here, but posting links to them is surely reasonable. Sharing a link doesn't mean one was the uploader – you're simply flagging that the artefact exists online. If one sought to determine whether every online photo was under copyright or not, there would hardly be an internet!