I think that flap position is likely the most obvious clue. Other indicators are more difficult to spot. Things like dust or rain water blown up from the runway by engines under high power, blurred images of tires that indicate whether they are turning. Other clues relate to the profile of the aircraft. Takeoffs usually result in a more nose-high angle than landings. The MD11 you show is likely taking off as the caption states. The flaps are not extended enough for a landing, and the high nose-up angle is contrary to a landing profile (unless the pilot severely got out of shape and had to over-flare to avoid a hard landing).