Hello,
I have recently published an addon that shows thumbnails for Cycles/Eevee image texture nodes:
Image Node Preview
I was asked if I could also add support for Octane image nodes. Before I start working on this, I would like to know if there is sufficient interest from Octane users for such an addon (the price is $7).
To prevent derailing this thread, please send a PM to me or reply in the addon thread if you would be interested.
From the screenshots I have seen so far it looks like the Octane image node does not have enough free space to fit a thumbnail inside, so I would probably show the thumbnail above the node, like in the Cycles environment node:
