It's a foul comment. My mum is master of the backhanded compliment, so I"m familiar with the genre:
"Oh, your hair looks so much better now you've let it grow a bit, it looked really butch short."
"Oh, you look so much better now you've lost a bit of weight"; "It's such a shame you got pregnant just now, you looked so lovely after you lost all that weight" (I'm 6 ft and a size 14 for the record).
Etc etc.
I have tried to pull her up on it, but she just gets narky and says, "why are you getting all scratchy, I'm just trying to pay you a compliment." Er no, you're not. But they'll never get it, don't waste your breath.
Though you could try the line, "Well, there comes a time when every woman has to chose between her face and her arse." Or, "Well, if you want the tits, you've got to pay the arse tax."