Sources & Maintenance
Drupal Research Install
Claims here were checked against a local Drupal install of core and the modules named below, rather than quoted from documentation.
Web Sources
| Source | URL | Guide Sections | Last Verified |
|---|---|---|---|
| Drupal.org - Including Default Image Styles With Your Theme | https://www.drupal.org/docs/8/theming-drupal-8/including-default-image-styles-with-your-theme | 4, 11 | 2026-02-14 |
| Drupal.org - Responsive Images in Drupal | https://www.drupal.org/docs/mobile-guide/responsive-images-in-drupal | 5, 8 | 2026-02-14 |
| Drupal.org User Guide - Concept: Image Styles | https://www.drupal.org/docs/user_guide/en/structure-image-styles.html | 1, 2 | 2026-02-14 |
| Drupal.org User Guide - Concept: Responsive Image Styles | https://www.drupal.org/docs/user_guide/en/structure-image-responsive.html | 5, 6 | 2026-02-14 |
| Specbee - 8 Ways to Optimize Images in Drupal (Core Web Vitals) | https://www.specbee.com/blogs/optimize-images-in-drupal-for-core-web-vitals | 9, 12, 14 | 2026-02-14 |
| Specbee - Setup Responsive Images in Drupal 9 | https://www.specbee.com/blogs/setup-responsive-images-in-drupal-9 | 5, 6, 8 | 2026-02-14 |
| Drupal.org - ImageAPI Optimize AVIF & WebP Module | https://www.drupal.org/project/imageapi_optimize_avif_webp | 9 | 2026-02-14 |
| W3C - HTML5 Embedded Content Spec (sizes attribute) | https://www.w3.org/html/wg/drafts/html/master/embedded-content.html#attr-img-sizes | 8 | 2026-02-14 |
| W3C WAI - Understanding Non-Text Content (WCAG) | https://www.w3.org/WAI/WCAG21/Understanding/non-text-content.html | 13 | 2026-02-14 |
| Drupal.org Security Documentation | https://www.drupal.org/docs/security-in-drupal | 14 | 2026-02-14 |
| Golems GABB - Image Optimization Guide (Drupal Image Styles & Responsive Images) | https://gole.ms/guidance/image-optimization-action-guide-drupal-image-styles-responsive-image-styles | 1, 9, 12 | 2026-02-14 |
Code Sources
| Module/Theme | Relative Path | Guide Sections | Drupal Version |
|---|---|---|---|
| Image module | core/modules/image/ | 1, 2, 3, 4, 7, 10, 14, 15 | 11.x |
| Responsive Image module | core/modules/responsive_image/ | 1, 5, 6, 7, 8, 15 | 11.x |
| Olivero theme | core/themes/olivero/ | 6, 15 | 11.x |
| Standard profile | core/profiles/standard/ | 5, 15 | 11.x |
| Core recipes | core/recipes/standard_responsive_images/ | 11, 15 | 11.x |
| Breakpoint library | core/lib/Drupal/Core/Breakpoint/ | 6, 15 | 11.x |
| Image toolkit library | core/lib/Drupal/Core/ImageToolkit/ | 3, 9, 15 | 11.x |