How do I turn on the Do-not-track feature?

support.mozilla.org/en-US/kb/how-do-i-turn-do-not-track-f...

Size	File	Width	Height
Original	7220413422_o.png	797	565
Middle	7220413422_m.png	500	354
Small	7220413422_s.png	320	226

(Original in Flickr)