Responsive images sizes attribute is broken

[k1sul1]

The sizes attribute will use the content_width global to ruin layouts. Simply put: If your content_width is 600, your images won't be wider than that, because the attribute value is (max-width: 600px) 100vw, 600px.

https://make.wordpress.org/core/2015/11/10/responsive-images-in-wordpress-4-4/

Change with wp_calculate_image_sizes filter.