Hi! the page has a gallery where you can download the thumbnails of videos that you want and is completely legal, so I guess it is also free to use as long as you leave the source of where the image was taken, I'm glad you liked the review is coming part 2, greetings!
P.S: there is also this section of the page which is somewhat similar to what I said a moment ago
OK. Thanks. I saw that page about downloading the thumbnails.