[wp-trac] [WordPress Trac] #50425: Do not lazy-load images which are very likely to be in the initial viewport

[WordPress Trac]

#50425: Do not lazy-load images which are very likely to be in the initial viewport
-------------------------------------------------+-------------------------
 Reporter:  flixos90                             |       Owner:  flixos90
     Type:  defect (bug)                         |      Status:  assigned
 Priority:  normal                               |   Milestone:  5.5
Component:  Media                                |     Version:  trunk
 Severity:  normal                               |  Resolution:
 Keywords:  has-patch has-unit-tests needs-dev-  |     Focuses:
  note                                           |
-------------------------------------------------+-------------------------

Comment (by adamsilverstein):

 I tend to agree that the browsers should be deciding exactly how and what
 to lazy load, ie. images in the viewport at load should load immediately
 regardless of a lazy attribute. It would be interesting to see some data
 about how impactful this is.

 I tested out the code in https://github.com/WordPress/wordpress-
 develop/pull/353 with some recent core themes.

 In general for single posts, things worked as expected, only the featured
 image at the top of the page excluded the `loading="lazy"` attribute,
 inline content images all included it.

 I noticed a potential issue however: when I set my home page to show
 recent blog post summaries, the themes included the featured image for
 each post: these images did lot include the lazy loading attribute.
 Similarly, visiting category archive pages showed a list of posts and
 these images were not lazy loaded - so I had a long page with images and
 none were lazy loaded - not ideal.

 After testing I am inclined to agree with @azaozz and feel
 `wp_get_attachment_image` should also default to lazy loading. Then we can
 clearly document for developers how they can opt out if they need a
 different behavior with the `wp_lazy_loading_enabled` filter.

-- 
Ticket URL: <https://core.trac.wordpress.org/ticket/50425#comment:8>
WordPress Trac <https://core.trac.wordpress.org/>
WordPress publishing platform