Hitting the spacebar on any comic-site on teamfortress.com (see URL) to add the next overlay causes the image to become distorted for about a quarter of a second. Same result with hardware-acceleration disabled.

I see same here on Win7 x64 with HWA on.. Mozilla/5.0 (Windows NT 6.1; WOW64; rv:28.0) Gecko/20100101 Firefox/28.0 Today's Nightly cset: http://hg.mozilla.org/mozilla-central/rev/518f5bff0ae4

Maybe this is the highquality downscaler? flip the pref image.high_quality_downscaling.enabled to check.

No, still happening.

There are 3 regressions #1 Flicker black screen every load words balloon Regressed by Bug 851785 #2 Blur image Regressed by Bug 716140 #3 Distorted image Regressed by Bug 853337 or Bug 853390 #1 Regression window(m-c) Good: L:\trunk\2013\03\firefox18-Mar-2013 1449 inbound http://hg.mozilla.org/mozilla-central/rev/e23e43a2c14e Mozilla/5.0 (Windows NT 6.1; WOW64; rv:22.0) Gecko/20130318 Firefox/22.0 ID:20130318130735 Bad: Flicker black screen every load words balloon L:\trunk\2013\03\firefox19-Mar-2013 0756 inbound Bug 830423 Avoid history view http://hg.mozilla.org/mozilla-central/rev/2c41bf87b4e5 Mozilla/5.0 (Windows NT 6.1; WOW64; rv:22.0) Gecko/20130319 Firefox/22.0 ID:20130319064414 Pushlig: http://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=e23e43a2c14e&tochange=2c41bf87b4e5 #2 Regression window(m-c) Bad: Flicker black screen every load words balloon L:\trunk\2013\03\firefox20-Mar-2013 0628 inbound http://hg.mozilla.org/mozilla-central/rev/1d6fe70c79c5 Mozilla/5.0 (Windows NT 6.1; WOW64; rv:22.0) Gecko/20130320 Firefox/22.0 ID:20130320044721 Bad: Blur image L:\trunk\2013\03\firefox21-Mar-2013 0616 fx inbound Bug 716140 Multithreaded image decoding http://hg.mozilla.org/mozilla-central/rev/a73a2b5c423b Mozilla/5.0 (Windows NT 6.1; WOW64; rv:22.0) Gecko/20130321 Firefox/22.0 ID:20130321045242 Pushlig: http://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=1d6fe70c79c5&tochange=a73a2b5c423b #3 Regression window(m-c) Bad: Blur image L:\trunk\2013\03\firefox22-Mar-2013 0831 inbound Bug 658909 http://hg.mozilla.org/mozilla-central/rev/3825fdbcec62 Mozilla/5.0 (Windows NT 6.1; WOW64; rv:22.0) Gecko/20130322 Firefox/22.0 ID:20130322070110 Bad: Distorted image L:\trunk\2013\03\firefox23-Mar-2013 1700 inbound Bug 849647 Get rid of message order optimization on Windows http://hg.mozilla.org/mozilla-central/rev/0a10eca0c521 Mozilla/5.0 (Windows NT 6.1; WOW64; rv:22.0) Gecko/20130323 Firefox/22.0 ID:20130323154724 Pushlig: http://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=3825fdbcec62&tochange=0a10eca0c521 #1 Regression window(m-i) Good: http://hg.mozilla.org/integration/mozilla-inbound/rev/baa90816699d Mozilla/5.0 (Windows NT 6.1; WOW64; rv:22.0) Gecko/20130318 Firefox/22.0 ID:20130318135932 Bad: Flicker black screen every load words balloon http://hg.mozilla.org/integration/mozilla-inbound/rev/25c76053d44a Mozilla/5.0 (Windows NT 6.1; WOW64; rv:22.0) Gecko/20130318 Firefox/22.0 ID:20130318141131 Pushlig: http://hg.mozilla.org/integration/mozilla-inbound/pushloghtml?fromchange=baa90816699d&tochange=25c76053d44a Regressed by: Bug 851785 #2 Regression window(m-i) Bad: Flicker black screen every load words balloon http://hg.mozilla.org/integration/mozilla-inbound/rev/c9c29cc97af0 Mozilla/5.0 (Windows NT 6.1; WOW64; rv:22.0) Gecko/20130320 Firefox/22.0 ID:20130320062640 Bad: Blur image http://hg.mozilla.org/integration/mozilla-inbound/rev/1407288d820b Mozilla/5.0 (Windows NT 6.1; WOW64; rv:22.0) Gecko/20130320 Firefox/22.0 ID:20130320074043 Pushlig: http://hg.mozilla.org/integration/mozilla-inbound/pushloghtml?fromchange=c9c29cc97af0&tochange=1407288d820b Regressed by: Bug 716140 #3 Regression window(m-i) Bad: Blur image Mozilla/5.0 (Windows NT 6.1; WOW64; rv:22.0) Gecko/20130320 Firefox/22.0 ID:20130320092341 http://hg.mozilla.org/integration/mozilla-inbound/rev/955bd7967d96 Mozilla/5.0 (Windows NT 6.1; WOW64; rv:22.0) Gecko/20130322 Firefox/22.0 ID:20130322161124 Bad: Distorted image http://hg.mozilla.org/integration/mozilla-inbound/rev/e1d71b13e35f Mozilla/5.0 (Windows NT 6.1; WOW64; rv:22.0) Gecko/20130322 Firefox/22.0 ID:20130322161223 Pushlig: http://hg.mozilla.org/integration/mozilla-inbound/pushloghtml?fromchange=955bd7967d96&tochange=e1d71b13e35f Regressed by: Bug 853337 or Bug 853390

It does not happen with these three prefs set to false: image.mem.discardable;false image.mem.decodeondraw;false image.multithreaded_decoding.enabled;false The last one has to be set when the other two are set, or Nightly crashes: Vista: https://crash-stats.mozilla.com/report/index/d2dec558-9e3f-4b50-954c-bf87a2131029 https://crash-stats.mozilla.com/report/index/43d493c3-683a-4f0c-aef1-d91422131029 Win7: https://crash-stats.mozilla.com/report/index/6418afbd-916e-42cd-a655-7a08b2131029 https://crash-stats.mozilla.com/report/index/6e665413-b403-4df8-9e8c-156652131029

#3 regrassion is triggered by Bug 853337

This goes back to Firefox 22 and there is no indication of widespread user impact here, not tracking but a low-risk uplift would be considered.

Now that bug 967985 has landed, only image.mem.discardable;false image.mem.decodeondraw;false have to be set as a workaround.

After all the changes to the image-rendering, I tried the URL to see if it was maybe fixed by accident. Unfortunately that's not the case. This year's comic doesn't show as much distortion as the one in URL, but it has some short flickers for me. http://www.teamfortress.com/bloodmoney/

Can't reproduce this on OS X, unfortunately. It does indeed appear to be Windows-specific...

Firefox 37.0.1 and Nightly Windows 7 and Ubuntu 14.04.2 re: Bug 1079627 - Make RasterImage support multiple decoders at once After bug 1079627 landed, instead of distorting the image for a bit, ...

... now the whole image-area has a short flicker. Last good revision: cac6192956ab (2015-01-16) First bad revision: 369a8f14ccf8 (2015-01-17) Pushlog: https://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=cac6192956ab&tochange=369a8f14ccf8 Last good revision: 53d0b45c24c5 First bad revision: 3caf22d78fc5 Pushlog: https://hg.mozilla.org/integration/mozilla-inbound/pushloghtml?fromchange=53d0b45c24c5&tochange=3caf22d78fc5