what do you do when you see someone smoking?

[Umm Sulayman]

For example on Instagram one of your followers outs up a picture of then smoking a joint or even shisha.
What would you do? Advise them or ignore?
And if the person is Muslim
@Mohammad..so advise only if u know them?
@Hassan.. Oh Yeah I smoke shisha but I stop others from doing it...SIKE. Use your brain please.
@safiyyah..yes me too, when I have to walk by a stranger smoking I cover my nose to let them know that it is repulsive. did you know that 2nd hand smoke is even more dangerous?

@mohammad..yes we must advise another muslim because Allah says that if we do not have amr bil-maruf wa nahy an il-munkar (enjoining good and forbidding evil) our iman is not complete & Allah will punish us if we fail to do so.
we should help one another, in a respectful and humble manner, because once Abdullah ibn Masud radiAllah anhu was asked "who are the living dead?" to which he replied "those who never command something good and never forbid something bad."...