The conversion from traditional structure to lazy loading is quite simple. Previously, whatever element the image was on had a background image property:
<div class="sd2-slide-background" style="background-image: url(<?php echo $image; ?>);"></div
Now, we've removed the background image property and replaced it with a HTML5 data property:
<div class="sd2-slide-background" data-sd2-slide-image="<?php echo $image; ?>"></div>
So all you need to do it make this change in the .thtml files of your lens, and it should work with Lazy loading.
If you've created custom lenses, you'll need to make this adjustment to any image elements that need lazy loading. This also works on <img> tags.