Google seems to be testing showing a super short product review in the image thumbnail in the search results. So Google will overlay at the top of the product image reviews like "sturdy," easy to move," "well made," "easy to clean," and so on.
This was spotted by Khushal Bherwani who posted this screenshot on Twitter:
I personally cannot replicate this, but this comes from the customer favorites section in the Google Search more shopping-focused search results.
I kind of like this short review in the image, it is really eye-catching.
Forum discussion at Twitter.