Even if they didn't want to go that route, What I've seen google do in the past is render every frame to a texture atlas, and write a CSS animation which update

Even if they didn't want to go that route, What I've seen google do in the past is render every frame to a texture atlas, and write a CSS animation which updates the background-position property at 60 frames a second, so at least you don't have to load 150 images at a time