There are tons of people in big cities that walk around with cameras all the time waiting for things for things to happen to take pictures . They go to events and stuff just to take pictures .
They have a link on the bottom of their web page on how to submit content . They also have staff that edit pictures taken off peoples phones . I’m sure that their staff that contacts people to get a story after something happens most likely ask people for the use of their pictures which they probably don’t pay much for if anything at all since they are required to submit an invoice with in so many days of publishing.
Didn’t realize so many people were just wandering in cities waiting to take pics. But guess it would explain the photos appearing super-fast.