Problem: What are the most important words?
man snoring with his wife covering ears with pillow on the bed
Answer: bed, cover, ear, snore, wife

Problem: What are the most important words?
troops arrive at their barracks to reinforce fellow troops following the siege by militants
Answer: arrive, militant, reinforce, siege, troop

Problem: What are the most important words?
an image of train going down the track past a city
Answer:
city, image, track