This isn't really new, Google has been testing ads and sponsored results in images for many many years. In fact, I believe ads came to image search some time ago. But we don't always see them.
Pigzilla informed on on Twitter they are now showing up on the mobile results. I was able to replicate them myself with the same query, so I don't think this is a test - rather something most of you all can see.
Of course, in mobile, you see two full sized image ads and then 2 half sized organic image results, which is sad. Here is a screen shot:
Here is what it looks like when you click on the sponsored label:
Forum discussion at Twitter.
