You've been able to save images on Google's app and mobile site without downloading them for a long time now. Last September, that functionality extended to non-image pages, and in April, customizable collections rolled out to replace saved pages. Now, certain image searches trigger the Google app to ask if you'd like to create a collection for the thing you're searching for — and images that fit the bill automatically save to the appropriate collection.
The functionality is pretty limited right now — we've seen Google suggest collections for memes, shoes, and quotes, but only in image searches. Even then, it's hit-or-miss depending on the specificity of your search. "Kermit the frog hearts" prompts you to create a collection for memes, for example, but many other meme-related searches don't.
If you've already created a smart collection, Google asks if you'd like to view it when you initiate a related search. When you save an image after creating a collection it belongs in, it will automatically save to that collection. Previously, images always saved to your most recently used collection — and that's still the case if there isn't a smart collection for the image to save to.
In a recent teardown of the Google app, our own Cody discovered evidence of these types of collections and automatic lists. There are strings for more than just images, including things like recipes, flights, and contacts — so it seems this is just a taste of much broader functionality to come.