You know, I really don't see all that much difference between the Gallery of Heroes image, and the pre-existing one...
Jhudiah has always looked healthy and robust to me - not necessarily curvy, but certainly not wafer-thin. And the only difference I can see between these images is their dimensions. She looks more curvy in the old image because it's 150x150 and it's a full-body shot. The new one is bigger, and cuts off just below her waist.
So, honestly, I don't really think they've made her thinner, it's just the way she was drawn.
And, incidentally, I've never considered any of the faeries to be anorexic. Granted, they aren't large, but that doesn't mean they all suffer from eating disorders. There's a big difference between being naturally thin (or fit) and being anorexic.
I also don't agree that the faeries are all scantily clad. After all both Fyora and Jhudora wear full length robes, and Taelia wears a fur coat (and won't animal activists be happy about that one). And granted some of the faeries wear tighter clothing, but they're still well covered - Illusen, the Space and Battle Faeries, Psellia...
Finally, if anyone would like to see an image of a faerie who isn't wafer-thin, then Ursula Vernon, one of my favourite artists has one in her DeviantArt gallery. You can find it here:
http://www.deviantart.com/deviation/7437279/ (the image, that is, not the gallery).