In reply to Harry.

The lazy load function built into WP Rig is a stand-alone component which can be ported to any theme and simply included. It has a default-on Customizer feature so the end-user can toggle it on and off as they like, and it is wrapped in conditional statements so it doesn't conflict with Jetpack and AMP which are the two most common lazy load plugins. The short term plan is to update the conditional wrappers to cover other lazy-load plugins as well, and the long-term plan is to shift the responsibly of lazy loading first to themes and then to WordPress core.