It came as a surprise, when I saw the image thumbnail in the search results while searching for “Chicken Biryani” in mobile, but when I tried to experiment by searching for other terms like “Italian Pasta” and ” Apple iPhone 7″, the thumbnail was missing from search results.
It seems, Google is again experimenting with thumbnail in mobile searches. However, there is no official confirmation from Google on this, but the search results look promising and it may help to increase the CTR of organic results.
In future, we may see images for all search queries. Here are the screenshots of few of the terms and this is how search results are looking in mobile.