The occasional cigarette on your own balcony, cause you just happened to have them lying around?
There was also an interview during the Atonement press where she said she got really fucked off one night because her lighter wouldn't work - she was in between takes, wanting to go home, wanting to have a smoke, and the damn thing wouldn't work, which resulted in a stream of fucks. If I remember correctly.
I can't find it though, and since I'm being the devil's advocate, I might as well not bother.
You asked for a candid picture of Keira smoking, I gave you one.