Google is now showing AMP results in Google Image Search. Will Barnes notified me of this on Twitter and I was able to replicate it.
Here is a screen shot showing the AMP logo in the image search results and if you click on the result title, it takes you to the AMP version of the Pinterest site.
Here is that screen shot:
AMP is clearly growing and growing in importance at Google, here is just one more place Google will show AMP results. It is now in the core mobile results, started in top stories and now in image search results.
Here is another site showing AMP in the mobile Google image search results:
Forum discussion at Twitter.