Lazy Load plugin has been quite popular recently. Atleast two Prototype ports have been created. First one by Edd Couchmann. Second one by Bram Van Damme. Congrats guys. Now Prototype people can enjoy lazy loading sweetness too.
I just added most requested feature. Sideways lazy loading of images in wide pages. I guess you could also call it right of fold_. Demo page herewide.html.
As an added bonus you get four new selectors: belowthefold, abovethefold, rightoffold and leftoffold. You can get some performance improvements using these. Attach plugin only to images below the fold with:
Or do something with all paragraphs far away right on wide page:
There are still some issues I would like to solve. In meanwhile download latest from the project page.