1725341 - Missing images and backgrounds since 91.0

Status: RESOLVED DUPLICATE of bug 1726606

(Core :: Disability Access APIs, defect)

Description

[gvi1]

User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:91.0) Gecko/20100101 Firefox/91.0

Steps to reproduce:

Upgraded from 90.02 to 91.0 opened amazon.de webpage thereafter

Actual results:

With 91.0 several images and backgrounds are missing so that thge web poages are hard to use. Tried firefox cleanup, created new profile but didn´t help. Also tried clear caches, computer restart, also had no effect.
After downgrading to 90.02 everything was shown and behaved as it should.
I am using 2 MacMini´s, both with MacOS 11.5.1, strangely the problem did not appear with 91.0 on my 1 year old 6 core model, but only with the other model which is much slower, has less memory and is 3 years older.

Expected results:

Correct webpage appearance like in 90.02 or other browsers

Comment 1

[BugBot [:suhaib / :marco/ :calixte]]

The Bugbug bot thinks this bug should belong to the 'Core::Layout: Images, Video, and HTML Frames' component, and is moving the bug to that component. Please revert this change in case you think the bot is wrong.

Comment 2

[Timothy Nikkel (:tnikkel)]

Would you be able to run a bisection using https://mozilla.github.io/mozregression/ to narrow down exactly which change caused this? That's probably the quickest way to get this bug diagnosed.

Comment 3

[Daniel Holbert [:dholbert]]

I suspect this is caused by this new feature in Firefox 91:
https://www.mozilla.org/en-US/firefox/91.0/releasenotes/
Firefox now automatically enables High Contrast Mode when "Increase Contrast" is checked on MacOS

(This was added in bug 1713015.)

You can disable this in Firefox's preferences - see https://support.mozilla.org/en-US/kb/accessibility-features-firefox-make-firefox-and-we#w_overriding-page-colors , "Overriding Page Colors". You probably want to choose the value "Never".

See bug 1725978 comment 4 for more detailed instructions.

Comment 4

[BugBot [:suhaib / :marco/ :calixte]]

Set release status flags based on info from the regressing bug 1713015