The millions of other sites you're referring to are largely static urls. When you visit something like "/explore/room-ideas" on Pinterest, it's a vast collectio

The millions of other sites you're referring to are largely static urls. When you visit something like "/explore/room-ideas" on Pinterest, it's a vast collection that is continually changing. Google decides to choose one image from that page as the "representation" and surfaces it in Google Image search results. If we had the image hash, we could reverse-lookup exactly what Google's intentions were and give the user a better experience. There may be other alternatives, I am not on the internal team focused on improving this experience--that team is in direct contact with Google.