Very rarely, but then, in the past it also happened very rarely althought that depends on the time the picture was drawn. As far as I know the T's were approx. 3 degrees (Celsius) higher than today somewhere around 1300. Also, there was a mini Ice-aged around 1726 (I believe).
We measure our winters by something called 'eleven city skating race' A race that happens approx. every 25 years because a lot of water needs to be frozen. The last one was around 1997, before that 1986, 1985, 1963.
So it might look as if winters were colder in the pictures but I wouldn't surprised if people would just paint a lot in cold winter because of the more pretty picture.
All in all, I don't believe the whole greenhouse crap yet, there's just to much evidence that this is a natural phenomenon. Evidence that Al Gore conveniently 'forgot' to mention in his movie.
But then again, if its natural, it won't be taxable, and we don't want that.