I've been using your plugin for a month now and it works nice. I had to add a style :
The only thing that would make it the best plugin ever is to add something more for responsive images.
Now your plugin load the normal attachments included in the post even in responsive mode. So yes it loads the picture only when scrolling but it's still the big one (but html resized) loaded.
Do you think you could use the "Medium, Small, thumbnails" sizes to load automatically a smaller image size for mobile users?
JS will not easily do the trick to enable adaptive images but there is many tricks to achieve that (like Hammy plugin)...
I think the main purpose of your plugin is to reduce the loading time. If you'd make it work with adaptive images also, that would be a huge improvement in performance !
Are you planning to include such improvements in your next releases?