Problem: What are the most important words?
a flag blowing in the wind in front of a blue sky with white clouds rolling by
Answer: flag, front, sky, wind

Problem: What are the most important words?
tv producer poses for a portrait during festival
Answer: festival, portrait, pose, producer

Problem: What are the most important words?
time lapse of clouds taken by the wind on a church
Answer:
church, cloud, lapse