Drupal

Drupal is a free, open-source content management system (CMS) used to build and manage websites, web applications and digital platforms. Known for its flexibility, security and scalability, Drupal supports structured content, multilingual publishing, user permissions and extensive customization through modules and themes. It is particularly suitable for complex, content-rich websites.

In the guide to responsive images in Drupal, you set up image styles, a responsive image style with sizes and a media view mode, and you never had to define a single breakpoint. That setup covers most images on most sites.

This article is for the next step: knowing where your layout changes, writing those widths down in a way Drupal understands, and using them for the one job where breakpoints really matter in the Responsive Image module, showing a different crop of an image on different screens. That's called art direction.