Have you ever used Facebook and clicked on "my friends"? Have you user browsed a page of forum posts where each user has their own picture? Have you ever looked at a slideshow on the internet? Have you ever gone on reddit or another aggregator site that shows thumbnails? These are hardly obscure use cases.
These things exist since way before 2000, and are working just fine without http/2+. I can think of another use case, though: sending lots of ads and videos from a single domain of a well-known ad company.
