Lazy load CSS background images?

This plugin looks to be very lightweight and efficient in lazy loading regular images and embedded content. I have a few CSS background images as well on my site. It would be great if it was somehow possible to lazy load these CSS images as well.

Here is some inspiration that may be of help to further improving this plugin to do something similar:
http://www.appelsiini.net/projects/lazyload/enabled_background.html

Thanks again for a good plugin!

– Michael

https://wordpress.org/plugins/bj-lazy-load/