The use of image thumbnails as part of a search engine is transformative and fair use. (law.stackexchange.com)
All the lists are scrollable, tapping on a Tweet opens it up so you can click links, view image thumbnails (depending on the picture service used) or action the normal Twitter responses - retweet, reply, etc.. (pocket-lint.com)
But if users are willing to accept that and lower - resolution image thumbnails, they can access Facebook quick, smooth, and cheap from the most remote corners of the planet. (beta.techcrunch.com)