The following scenarios should be tested to evaluate improved lazy-loading behavior with regards to optimizing hero images:

1. Remove lazy-loading not only for images marked with data-hero, but also those marked with data-hero-candidate. See Prevent SSR for amp-img occurring after second paragraph #141 (comment)
2. For images not marked with data-hero, check if there is a noscript > img to copy an existing loading attribute from. See https://github.com/ampproject/amp-toolbox-php/pull/141/files#r611001917