Lazy Load doesn’t work when image ID is not used as class

After recent update images don’t load using lazy load unless you specify the exact image ID with a class wp-image-*For example wp-image-172626.

For example:

This will never load:
<img class="aligncenter size-full" src="#" alt="random" width="1100" height="800" />

It must be:

<img class="aligncenter size-full wp-image-172626" src="#" alt="random" width="1100" height="800" />

That’s not really a good way to load images because not everyone uses those IDs for images. They are there for default but I have removed them for many images as they serve no purpose.

Please fix it.

The page I need help with: [log in to see the link]