SCP-173 has now been updated to reflect Kato's requests, with enormous proofreading help from Photosynthetic and Zyn.
(And, to be clear, we are very happy to comply with any request he might make.)
And, goddamn, this is pretty awesome of him. His reluctance is understandable; as a community, we did literally steal his art piece and redefine it to a significant portion of the world. And I think most of us are honestly sorry about that, despite how much it's benefited us. It's actually really, really cool that he's letting us keep the picture. We owe him a lot of thanks.
Also, major thanks to Lotims for prompting Kato to reply to us after all this time! Hopefully he doesn't begrudge us our suspicion of him too much!
http://www.scp-wiki.net/scp-173 « Check for the new disclaimer. We can tweak this, of course, just so long as it reflects Kato's requests.
As a side point, I think — not for legal reasons, but for reasons of artistic respect — we should not hide this under a collapsible or anything else like that. The artist requested that we change the framing of his work, and keeping it visible and clear to anyone is part of that. To paraphrase Zyn, I'm willing to kick immersion in the teeth to make the artist that accidentally helped create our entire site a little more happy.
EDIT: Posted comment — http://www.scp-wiki.net/forum/t-76692/scp-173#post-2106398
EDIT: If we want to make the disclaimer prettier, I don't have any objections to that. Presently, someone suggested that we put it in a quote box and center it. I'd be fine with that. Thoughts?