Re:AVIF support enabled by default in Firefox 86
by ehsankia on Sunday January 10, 2021 @05:47PM
(#25721060)
Or maybe, you only notice that one because it's obvious, but most of the time when you see a JPG which you think has finished loading, it's actually still not done but it looks like it's done, as in the example above.
I honestly could not tell it was still going after the 2nd progressive layer.
I guess it depends at what point it does the first render. I rarely see images load progressively in the first place, but when I do it's usually with an initial render that looks like 1967 needs their image back. My guess is that it's busy downloading the many/largeish js/css files that prevent it from getting very far on images before the DOM is ready for initial render.