Ive been following this discussion with interest. I've downloaded the two robin images, loaded them into photoshop and sampled a few spots. Like Rob, within the tolerances of error the samples are the same.
My thinking is that its a browser issue rather than a system issue - what browser are you using? Have you tried a different one?
This page
http://www.color.org/version4html.xalter will show you how well your browser is reading ICC profiles.
In firefox you might need to enable colour management see this page
http://ntown.at/2013/12/28/firefox-color-management/ I've found that IE11 does a better job that firefox 34 even with colour management enabled but I've not tried Chrome or Safari