Just got this email from Google because I globally introduced amp-img and they discovered 163 failed pages. No doubt there will be even more pages that do not conform.
Google systems have detected that some of your AMP pages do not meet our guidelines and will therefore not show Google Search AMP-related features. The following report provides examples of pages with errors:
I think the major problem is image inline styles are now not allowed.
I have been pondering on the best approach to prepare all existing web pages that conform to the Google Mobile Test. I introduced image inline styles wherever necessary to pass the mobile test.