This isn't a bump. I just realized this was actually my first post here and I didn't introduce myself at all. I've been lurking for a while and honestly thought I had posted at least a few times already.
At any rate, I tried to be short and to the point in my original because I know that many here are so knowledgeable about color management issues I thought it better not to waste their (your) time. I now see that my post may have left a flavor of "your forum is for nothing but helping me, so just do it already", in your mouth. I apologize if that seemed to be the case.
So, I've been lurking here and have gained a lot of understanding, but unfortunately it hasn't been enough to avoid whatever issue I'm having.
To un-short-and-to-the-point my original . . . I'm processing a DSLR captured image, after editing with CNX2 and outputting a TIFF with the original Nikon Adobe RGB profile (which Photoshop can use as the profile is also on my machine), further tweaked in Photoshop CS5, converted to sRGB with a small shift in some saturated colors that I can live with, and then saved for web. Everything seems to be fine. The previews look right in the Save For Web and Devices dialogue, with the original showing preview based on the embedded (at that point already sRGB) profile, while the optimized output file is set to preview with the internet standard (what a web browser should show me). Except . . . it isn't what I actually get.
What I can do to emulate perfectly what I get in Firefox is to do a softproof using the Monitor RGB option. This should tell me the problem, I think, but I don't get it still.
I'm wondering if it is an issue of having a v4 profile (if that is indeed what I have) vs. v2. I don't know how to check or figure out which I have, though.