Which picture is different and why?

I can see three LEAVES.

Picture 4 is different because the trees don't have any leaves. In picture 1,2,3, the trees have many leaves.

I can see a LEAF

The man in picture 2 is different because he has moustache. The men in picture 1,3,4 don't have moustache.

The paper is different because it has square shape. The clock, the plate and the balloon are round (have round shape).

I can see A PERSON.

It's a SQUARE

The cloud is different because it's not an animal. The cow, the sheep and the goat are animals.

I can see a (bus) DRIVER.

It's round.

I can see TWO MEN.

The doctor in picture 2 is different because she is a woman. The teacher, the farmer, the driver are men.

Picture 2 is different because there is one child in the picture. In picture 1,3 and 4, there are 2 children playing.

I can see FIVE CHILDREN.

The horse is different because it's an animal (it's a living thing). The bike, the motorbike and the car are not animals. They are machines.

I can see A CHILD.

I can see a FARMER.

I can see A MAN.

I can see THREE PEOPLE.

I can see a PLATE

Picture 1 is different because she is riding a bike. People in picture 2,3,4 are walking.