While she certainly looks bad in those photos, I think the combination of no makeup and the angle of the shot (under-the-chin doesn't do anyone any favors) is what's done her in. For comparison, here is a recent photo on the set of Australia's Next Top Model. For 50, I think she looks very good - just not very thin.
And here, at the ANTM premier last week. Again, not thin, but could be much much worse. With better styling, I think she'd look loads better and not so washed out...
I know, I was shocked too to see these! She has a bloat look to her, like she's been partying a lot and has put weight on quickly. Still her skin is beautiful and should she lose it again as quickly as she gained those incredible bones will re-emerge once more.