This option sets how early a lazy-loaded image is loaded before entering the visible area of the page (viewport). For example, the default of 500 px means that an image is loaded when it’s closer than 500 px to the viewport. A higher value means that an image will be loaded very early, which may trigger some warnings on web speed testing tools; with a lower value, your visitors could see a blank box for a very short time before the actual image is loaded.
If unsure, don’t change it.
Note: It is not possible to disable entirely ShortPixel AI’s lazy loading, as it is required by the plugin to work properly. You may, however, exclude certain images from being lazy-loaded. For more information, click here.