Whats the difference

What's the difference? There are four pictures for each question , One of them different , come to find out it !============ Game features ==============
1. Simple, fast-paced 2. The most appropriate to pass the time3. Brainstorm, brain activation 4. Cute style , the public image 5. The young and old , healthy game 6. Category rich , ever-changing 7. The quiz is updated regularly