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.
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.