As another lazy loading hater, I think that's a good thing. If a website wants to use lazy loading, it should be handled by the browser, rather than using a custom JavaScript code that the webpage requests. There being one universal method means that there is only one setting that I need to disable to avoid lazy loading. Currently I use a userscript based on heuristics to load all lazy-loading images, but it often doesn't work, as websites use a wide variety of methods to implement it.
Also, incorporating lazy loading into the browser would make NoScript viable in far more websites. Most of the time the only reason why I consider enabling JavaScript for a website is to view lazy-loading images, everything else works good enough (or better) without JavaScript. With lazy loading being done by the browser, almost no website I come across would have this problem, unless they choose to intentionally break without Javascript. Of course, this wouldn't be a problem in the first place without lazy loading, but alas, here we are, with most websites using it.
I don't necessarily expect browsers that implement it to have a user-visible way to disable lazy loading, though, so you may be out of luck there. You _might_ be able to create userscripts that force non-lazy loading on all potentially-lazy elements by using the opt-out frob browsers would add for websites.
I would hope that Firefox would have an about:config setting to disable it, but with the direction they are going, removing customizability left and right, who knows. Normally I would have also expected addons to disable this browser-side lazy loading, but since Firefox 57 they are more like glorified userscripts, so they probably wouldn't be able to.
On Chromium side, maybe Vivaldi and the like could provide the option to disable it, if it is not too difficult of a change on Chromium. But for sure, I would be very surprised if Chrome offered that option, so not much of an improvement for Chrome users, or maybe even a deterioration if sites start to adopt it even more, now that it is supported natively.
> Currently I use a userscript based on heuristics to load all lazy-loading images, but it often doesn't work, as websites use a wide variety of methods to implement it.
Would you mind sharing this script? I use NoScript heavily and something would certainly be better than nothing in a lot of cases.
Mine was based on the answer here[1], now I see that the script in the answer was edited after I started using it. I should try the new version to see if it works better.
My experience with the previous version was that while it sometimes worked, on some websites it broke more than it fixed; and when I modified the script to account for that issue, it broke something somewhere else, as websites use very different methods to display images that I couldn't imagine (hence I welcome a standard way of doing it). So I ended up using the script on a whitelist basis instead. Maybe the new version works more properly, so that I can enable it globally again.
Also, incorporating lazy loading into the browser would make NoScript viable in far more websites. Most of the time the only reason why I consider enabling JavaScript for a website is to view lazy-loading images, everything else works good enough (or better) without JavaScript. With lazy loading being done by the browser, almost no website I come across would have this problem, unless they choose to intentionally break without Javascript. Of course, this wouldn't be a problem in the first place without lazy loading, but alas, here we are, with most websites using it.