This is what it looks like when you use a gray-scale version of the color map as a bump map.

It vaguely has some correlation to the real hills and valleys, but it isn't right. It's true that it no longer looks flat. But it doesn't have the right shape at all.

And there are extra bumps wherever there was a specular highlight burned into the texture.

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Renderosity forum reply notifications are wonky. If I read a follow-up in a thread, but I don't myself reply, then notifications no longer happen AT ALL on that thread. So if I seem to be ignoring a question, that's why. (Updated September 23, 2019)