For some time I've occasionally used the ones for the visually impaired because they were easier to get right. But they also messed those up. I get a load of fire hydrants, cars, stairs and bicycles and motorcycles and traffic lights. Sometimes the pictures just repeat. I don't think the stock of images is that big. But they could look at other things instead of just correctness. Like your mouse movement and how long it takes you. Not sure if they do that.