No matter what I change "My preferences/math" to, I always get the same thing, which is mostly PNGs. I've checked on the blahtex web pages that I can use MathML in my Firefox but the preferences on wikipedia.org don't seem to do anything. I haven't found anywhere an explanation of why the preferences/math tab does nothing, not in the preferences tab, not in the help for the preferences tab, not in the discussion pages.
Can anyone explain to me what's going on, and possibly update http://en.wikipedia.org/wiki/Help:Preferences#Rendering_math and even http://en.wikipedia.org/wiki/Special:Preferences?
Best,
Sébastien Loisel