I'm not quite sure if I understand it right that's why I need some clarifications. If it allows uploading then people can probably get images from the internet and upload it here to earn?
Yes people can do that. But there is a moderator to check the images. Not all images are accepted according to their terms. That simply means those images are not going to be accepted.
I think that the team will hire a whole staff of people who will monitor this and it is unlikely that anyone will be able to constantly deceive the system.