“It is not a bug, it is a feature.”
That is what the programmer says when users complain.
It is implemented like a bug.
It basically slows down 99% of the users who want to quickly find an image in their image library, now you have to click every 40 images or so to load more, when you have 1000 pictures in your library it will take you forever to scroll till the end. They could have easily offered users the possibility to make a choice between infinite scroll and the new button or found a possibility to automatically detect people with screen readers and automatically show them the button and keep infinite scroll for the rest. At the very least a little slider on the media library to turn on or off the scrolling would have been smart. Right now the change feels like a bug and cripples most peoples user experience.