Help From Google Addressing AMP Logo Guidelines
AMP logos are getting more and more widely used but it seems that not everyone knows how to implement them properly. The topic was raised by Elena L. from Google. She posted a help thread on the Google Webmaster Help forums which is straight to the point. Elena said that she noticed how a number of users are not including a valid AMP logo in the specific pages, or are doing it wrong in their structured data markup.
Here are the exact fixes that Elena commented:
Missing Logo Target: How to fix? Specify a logo value in the logo.url field of the AMP page’s structured data markup.
Broken Logo Link: How to fix? Specify a logo value with a valid absolute URL in the logo.url field of the AMP page’s structured data markup.
Square Logo Format: How to fix? Follow the general Logo guidelines. If your site uses a Content Management System (CMS) with a default square logo, check if they offer any options to override it.
Illegible Logo: How to fix? Use a logo version with darker text or imagery to provide enough contrast against a white background. However, refrain from including a dark background in the logo itself to make the light items stand out. Ensure that the logo text or images are not too dense to be legible when viewed at their display size in the carousel.