There should be a seamless animation between the images.
There is a white flicker / flash between the animations. Its also happening with the HTML Content Examples. Its not a Image only problem.
Firefox 58, Windows and Mac.
6.4.
https://foundation.zurb.com/sites/docs/orbit.html
Discovered that bug too. Published a post in the Foundation forum, no answer. But the video I made is here :-) It fails since version 58.0b3 of Firefox. The bug is still there with version 59b3, but a bit "less" visible.
I bisected the builds and the following change is the cause

2018-02-10T10:42:11: DEBUG : Using url: https://hg.mozilla.org/integration/autoland/json-pushes?changeset=fa94f7205173d34f23975c6af9cb95237b28c8b8&full=1
2018-02-10T10:42:12: DEBUG : Found commit message:
Bug 1190721 - Throttle animations that produce any transform change hint if the target element is out-of-view. r=birtles
And unthrottle them on every 200ms just like we do for transform animations on
the compositor. To unthrottle the transform animations properly, we need to
update UpdateLastTransformSyncTime each time we compose the style for the
animations instead of updating it when we send the transform animation to the
compositor. That's because display item for transform is built even while we
are throttling the transform animations for some reasons, so if we updated the
last transform sync time there, the time will not match what it should be.
MozReview-Commit-ID: GwMzJqUlzd2
https://hg.mozilla.org/mozilla-central/rev/fa94f7205173d34f23975c6af9cb95237b28c8b8
Related https://bugzilla.mozilla.org/show_bug.cgi?id=1424506
Summoning @hiikezoe ✨
cross referencencing https://bugzilla.mozilla.org/show_bug.cgi?id=1437272
For other testers, try mozregression https://github.com/mozilla/mozregression/releases
Can anyone confirm that this still happens in Firefox 59 and 60? https://bugzilla.mozilla.org/show_bug.cgi?id=1425213#c26
This is still present in Firefox Nightly 60.0a1 (2018-02-09)
I can reproduce the all of the following issues under Firefox 60.0a1 (BuildId:20180210220139) on macOS 10.13.4.
New binaries at https://bugzilla.mozilla.org/show_bug.cgi?id=1437272#c8
At least transitions are often used and the behavior before Firefox 58 was totally ok.
Not sure why the change was done.
https://bugzilla.mozilla.org/show_bug.cgi?id=1437272#c8 FF 60a1 seems to be fine.
Cannot be reproduced it anymore with Firefix 60. I guess this was a browser bug with animations and that we couldn't resove it. Closing this issue.
It was/will be resolved in Firefox 60, see https://bugzilla.mozilla.org/show_bug.cgi?id=1437272#c38 ;-)
And yes it was a browser bug / regression on their side.