This error will show up in Google Search Console (AKA Webmaster Tools or WMT) if there is an error with some or all of your AMP pages.
Error
Explore a collection of blog posts on robinjescott.com, delving into various aspects of errors, their causes, solutions, and prevention strategies.
New Google AMP Warning “Image size smaller than recommended size”
If you’re running AMP for fast loading pages on the mobile web (and, if you’re not, you should give it a try, it’s awesome!), you maybe got a notification in Search Console (AKA Google Webmaster Tools) that “Image size smaller than recommended size” for some or all of your AMP content.