How to Preload Critical Images in WordPress

Why You Need It

Lazy loading all images (including above-the-fold) can cause a flash of unloaded content. Preloading critical images ensures the visible content loads immediately.

How to Enable this Feature

Step 1: Navigate to Settings

Click into the Classic Monks plugin settings, then the Performance tab, Lazy Loading subtab.

Step 2: Enable the Feature

Toggle on the feature.

Step 3: Save and Test

Click Save Changes. Test on the frontend.

Common Use Cases

Hero sections

Hero images should load immediately (not lazily) to avoid a flash of empty space.

Above-the-fold images

Any image visible on first load should be preloaded, not lazy loaded.

Troubleshooting

The feature is not taking effect

Cause: The toggle is off, or a caching plugin is serving the old page.
Fix: Verify the toggle is on. Clear all caching layers.

The feature breaks another plugin

Cause: Another plugin depends on the functionality that this feature disables.
Fix: Disable this feature if it breaks another plugin.

Developer integration

This feature registers 1 WordPress hook in monks-preload.php:

Actions:

• wp_head calls cm_preload_critical_images() (Outputs link preload tags for featured images and logos (priority 1))

// Hooked in monks-preload.php
add_action( 'wp_head', 'cm_preload_critical_images' );

The feature modifies WordPress behavior by registering or removing hooks. Disabling it reverses those changes and WordPress returns to its default behavior.

Before you enable this feature

1. Test on staging first to verify no conflicts with your theme or other plugins
2. Check dependent plugins that may rely on the functionality being modified
3. Monitor after enabling for any unexpected behavior on the frontend

How it works under the feature

This feature runs during the WordPress initialization phase. When enabled, its PHP code registers hooks that modify specific WordPress behaviors. The changes are non-destructive and reversible.

No database schema changes are made. The feature state is stored as a boolean value in the wp_options table and can be toggled at any time from the admin settings.