Digital picture exchange is like trading your toy cars with your friend, but instead of toy cars, you trade pictures. You take a picture with your camera or phone, and then send it to your friend using the internet. Your friend receives the picture on their computer or phone and can see the picture you sent them.
Imagine you have a special toy car that you really like, and your friend has a toy car that they really like too. You might want to trade cars with them so you can play with their car for a while and they can play with your car. That's kind of like trading pictures in digital picture exchange.
But instead of having to physically give your friend your picture or keep it on a piece of paper, you send it to them over the internet. It's like sending a message to your friend with a picture attached.
When you send a picture, it gets turned into a bunch of numbers and letters called code, which is like a secret language that only computers can read. Your friend's computer can take that code and turn it back into the picture you sent. That's how pictures can travel across the internet so quickly, even though you might be far away from your friend.