The page on which I first noticed this appearing is this one: http://flukeout.com/bye-cassie/ . Note how moving the mouse in Firefox causes flickers in the photo boxes, while Chrome does not display this issue. I've put together a minimal reproduction which I'll link shortly. Interesting things to note: * I don't see the flickering issue if I change the minimal reproduction to use img elements rather than div elements with backgrounds * The flickering disappears if I comment out the <div class="throbber"> and children. The flickering is much more intermittent in the reduced case than the original, so be prepared to whirl the mouse around for a few seconds.

jrmuizel said this is your wheelhouse, Timothy.

I figured out how to make a self-contained testcase that requires no interaction. Just watch it for about 5 seconds and the flicker should be noticeable.

It reproduces on my Win10 machine.

Regression range https://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=cac6192956ab&tochange=369a8f14ccf8 So quite likely bug 1079627, I think I've seen similiar regressions from bug 1079627 where is seemed like decoding had been made more "async" then before that bug. Looking at the changesets, that's probably because they changed us from using a strategy of "sync decode until we've hit a certain time limit" to "sync decode if the compressed image file is smaller than x bytes", where x is 16kb. The images on http://www.joshmatthews.net/bug1261442/byecassie.html are ~60kb, so they don't get sync decoding.

Im facing same kind of issue, I used change img src in each 5 seconds by s3 url. And the image is flashing after loading. So is there any fix for it.