Just load all images. No JavaScript! Let the browser handle it. I hate when web sites only display 1-3 pages worth of content and unload/load more when I scroll. The JS code for that uses more resources then pulling everything would. It's a user nightmare, where I cannot use "find" and I can't zoom out, or scroll fast. The browser can easily handle 10,000 DOM elements. There is already optimizations in place in browsers which solve render issues. Beating the browser at it's own job will require a tremendously amount of work. These problem was already solved when computers only had 256MB of memory. And your web site would be blazingly fast today if you did not complicate things.
So no, browsers don't have these problems solved out of the box. And it seems like what they are implementing will suffer from the exact problem I described here too.
I think you might also be thinking of bad implementations of infinite scroll which isn't what I am talking about. Have you never use something like photos.google.com? Scrubbing/scrolling to an arbitrary point in time is honestly a great user experience. Would you rather wait hours/days for a webpage to load all the past photos images you've ever taken? Or have to deal with pagination and click through hundreds of pages to find what you want?
