Option to keen load once on screen images have loaded

[msaspence]

It would be nice to have an option which when enabled after blazy has loaded the visible images on the page it starts to preemptively load image in small batches working its way down the document.

[dinbror]

Hey @msaspence .

I like the idea but I also want to keep the file size down. I'll put it on the "ideas" list and consider it.

Thanks