Google have recently implemented 1200x image size for amp pages which cause error on search console for the sites that use smaller dimension than what they recommended.
The dimension size is supposed to be implemented for featured images, 1280×720 pixel is the recommended size for search console to comply with amp page.
To solve this error, there are three ways which I’m going to share with you for static sites users, WordPress and Blogger users. The tip is for all but it works perfect for WordPress users with all methods.
Here are the solutions to solve Amp small size error on search console;
Use at least 1200x images for featured images
This tip is work for all web platforms, WordPress, Blogger, static sites and other CMS. Due to these changes which is working on Google, many webmasters and developers recommend to use large images to prevent site from getting the above error.
Set image size for structured data
This tip is working for all web platforms, just like above but it does not require large image to get pass from search console. This one need someone with basic knowledge of web programming or theme or plugin with structured data configuration. For WordPress users, just install Structured Data plugin on WordPress repository, then set default image to recommended size.
Use AMP For WP plugin
This tip is working for only WordPress users who are prefer not to use recommended amp plugin offered by Google. The AMP for WP plugin contains the option for creating default image size for structured data, which convert featured images to required size just like above tip. This plugin is completely free, you can access it in WordPress plugins repository.