TIP: I found out yesterday that html5 has a built in attribute for lazy loading images
adding the attribute
loading="lazy" to img tags uses the browser facility to lazy load without scripts. The coverage is currently around 74% browsers but of course there is no error on unsupported and it is one less script to run.
I've tested it on an ecommerce site in Chrome and it works fine. So, you could add this attribute to an override in your CMS (I use Joomla)
can I use: https://caniuse.com/?search=lazy