Problem: What are the most important words?
Two clocks on post next to building in street.
Answer: clock, post, street

Problem: What are the most important words?
A doctor and his assistants are working inside a hazerdous tent in Africa to solve the Ebola epidemic.
Answer: assistant, doctor, tent, work

Problem: What are the most important words?
old brown leather wallet with a dollar bill sticking out isolated on white
Answer:
bill, stick, wallet