Image Prioritizer

Skildring

This plugin optimizes the loading of images (and videos) with prioritization, lazy loading, and more accurate image size selection.

The current optimizations include:

1. Ensuring fetchpriority=high is only added to an IMG when it is the Largest Contentful Paint (LCP) element across all responsive breakpoints.
2. Adding breakpoint-specific fetchpriority=high preload links for the LCP elements which are IMG elements or elements with a CSS background-image inline style.
3. Applying lazy-loading to IMG tags based on whether they appear in any breakpoint’s initial viewport. (Additionally, sizes=auto is then also correctly applied.)
4. Adding fetchpriority=low to IMG tags which appear in the initial viewport but are not visible, such as when they are subsequent carousel slides.
5. Reducing the size of the poster image of a VIDEO from full size to the size appropriate for the maximum width of the video (on desktop).
6. Lazy-loading VIDEO tags by setting the appropriate attributes based on whether they appear in the initial viewport. If a VIDEO is the LCP element, it gets preload=auto; if it is in an initial viewport, the preload=metadata default is left; if it is not in an initial viewport, it gets preload=none. Lazy-loaded videos also get initial preload, autoplay, and poster attributes restored when the VIDEO is going to enter the viewport.

This plugin requires the Optimization Detective plugin as a dependency. Please refer to that plugin for additional background on how this plugin works as well as additional developer options.

👉 Note: This plugin optimizes pages for actual visitors, and it depends on visitors to optimize pages. As such, you won’t see optimizations applied immediately after activating the plugin. Please wait for URL Metrics to be gathered for both mobile and desktop visits. And since administrator users are not normal visitors typically, optimizations are not applied for admins by default.

There are currently no settings and no user interface for this plugin since it is designed to work without any configuration.