Responsively Lazy - lazy load responsive images
Responsively lazy is a JavaScript library for lazy loading responsive images. It was released in 2015 and currently has 1000+ stars on GitHub. It's SEO friendly and truly lazy (absolutely no unnecessary requests).

I was looking for a lazy loading solution for a long time, mostly because I deeply care about web performance and I wanted to bring this benefit to all Bear CMS and powered websites. There were a couple of libraries, and there was srcset, but all of them did not match my requirements. Internet Explorer 11 was kinda popular back then too.

So one evening, an idea hit me. It felt weird because I've never seen such a solution, and it seems much better than I've ever dreamed of. After a few hours of coding, I could not believe how well it worked.

I've published it, and now Responsively Lazy is one of the most popular lazy loading libraries out there. Check it out at GitHub and take a look at the announcement post.