You can see the folders around 40 seconds in to this video:
https://m.youtube.com/watch?v=COBQqwKQX_I
https://m.youtube.com/watch?v=COBQqwKQX_I
Going by the screenshots from the official blog, you will be able to resize the tiles inside folders.Great catch! Glad it looks smooth. I hope you can resize them once they're in a folder...