Image Lazy Load Forcer

WHAT IT DOES

Image Lazy Load Forcer is a browser extension that forces lazy loading on all images on a webpage by adding the loading="lazy" attribute and, for older browsers, using IntersectionObserver. Lazy loading delays the loading of images until they are about to enter the viewport, which can significantly improve page load speed, reduce bandwidth usage, and improve overall performance. Users can toggle the feature on/off, set a custom threshold (in pixels) for how early images should start loading before entering the viewport, and the setting is saved per website. The tool also adds decoding="async" for improved image decoding performance. The tool is ideal for users who want to improve page load performance on image-heavy websites, save bandwidth, or reduce CPU usage on low-powered devices.

WHERE IT RUNS

Image Lazy Load Forcer runs on any webpage, overlaying a floating panel that does not interfere with page content. It operates entirely in your browser as a lightweight userscript, modifying image attributes and using browser APIs for lazy loading. It works on any page, whether static or dynamic, with no external dependencies. All settings are stored locally using GM_setValue—no data is ever sent to any server.

HOW TO USE

After installation, open the floating panel by clicking the extension icon. The panel shows the current status (Enabled or Disabled) and a toggle button to enable or disable lazy loading. Use the "Threshold (px)" input to set how many pixels before an image enters the viewport it should start loading (default: 0). A higher threshold loads images earlier, which can improve user experience at the cost of some performance. Click the "Set" button to apply the threshold. Click the "Reapply" button to manually reapply lazy loading to all images on the page—useful after dynamic content loads. The setting is saved per website, so your preference persists across visits.

REAL MECHANISM — WHY THIS WORKS

Most lazy loading implementations require manual coding or specific frameworks. Image Lazy Load Forcer applies lazy loading retroactively to any page using the browser's native loading="lazy" attribute and IntersectionObserver fallback. When enabled, the tool iterates over all img elements on the page and adds the loading="lazy" attribute. For images that are already loaded or have eager loading set, the tool skips them. For older browsers that don't support native lazy loading, the tool uses IntersectionObserver to monitor images and set their src when they intersect with the viewport. The threshold value controls the rootMargin of the IntersectionObserver, effectively loading images earlier. The tool also adds decoding="async" to improve image decoding performance. A MutationObserver watches for dynamically added images and applies lazy loading to them automatically. When disabled, the tool removes the loading="lazy" attribute from all images and disconnects the observer. This approach ensures comprehensive, performant, and fully private lazy loading without requiring any external services or network access.

THE PANEL

The floating panel is fully draggable and remembers its position per site, snapping to the edges of the viewport when dragged near them. You can collapse the panel to a small icon to minimize screen distraction and expand it back with a single click. The panel is resizable from the bottom-right corner, giving you more space to view controls. Press the Escape key to close the panel instantly. The panel remains open across page navigation within the same domain, maintaining your current view state. All preferences—panel position, enabled state, and threshold value—are saved per domain for a seamless experience.

PLEASE NOTE

Image Lazy Load Forcer requires the free BotGentz extension to be installed and enabled, as it relies on the cross-extension messaging API provided by BotGentz for DOM access permissions. The tool modifies image attributes and may not work on images loaded via JavaScript or with complex loading logic. Native lazy loading is supported in modern browsers; older browsers may use IntersectionObserver fallback. The threshold value is in pixels and controls the rootMargin of the IntersectionObserver. All settings are stored locally in your browser using GM_setValue. No image data, page content, or usage information is ever sent to any server. The extension does not read, store, or transmit any personal information. It only modifies image attributes at your request.