Google's product listing ads are now available in mobile Google Image Search. They're placed above the list of image search results and look much like the shopping ads from web search. Google also shows a colorful list of related keywords you can add to your query: brands, colors, categories and more.
"Whether they're looking for a new sofa or the perfect pair of earrings, people who search and shop on their smartphones at least once a week say that product images are the shopping feature they turn to most. And it turns out, the top questions Google Images users ask us are 'What's the price of this?’ and ‘Where can I buy it?'. That's why we are introducing Shopping ads on image search," informs Google.
Here's the "shop on Google" section from web search.