You can possibly disable AVIF support that got enabled in 93 and later via about:config.

• about:config => image.avif.enabled = false
• https://www.mozilla.org/en-US/firefox/93.0/releasenotes/

• https://support.mozilla.org/en-US/kb/about-config-editor-firefox

Ok, thank you, I have changed it to false, but now the photos on some websites won't even load. I have closed the browser and reopened it also...

Yes, I was already afraid about that. Some websites assume that recent Firefox versions support AVIF even if it doesn't reveal this via the HTTP request headers Firefox automatically adds image/webp and image/avif and image/jxl to the HTTP accept header when those formats are enabled.

• https://searchfox.org/mozilla-release/source/netwerk/protocol/http/nsHttpHandler.cpp#line-218

You will have to enable AVIF (i.e. reset the pref) if you encounter issues with websites and possibly use a tool or extension to convert downloaded images to JPG. You can search the Add-ons website or Google for a possible solution.

Can FF just update the browser to remove all of this? Because it is their update that is causing the problems. Now some other websites are not even loading. I use a website like amazon where I live, and the website loads but now each individual product page doesn't even load..... This is a problem.

WARNING: Changing preferences through this interface not officially supported Hidden settings edited using the about:config tool are explicitly not supported, which means that Mozilla makes no guarantees they will be supported in the future, or that Mozilla will fix them if they break. Mozilla does not test these preferences, and will not in the future. That includes security and performance testing which these preferences may affect.

So how to resolve this issue? Especially for the websites that won't even load pictures? FF needs to fix this.

Hi Jeff, Would you be able to provide a web address (URL) of a site where the problem occurs, and which image you are trying to save?

When I test it on this thread https://support.mozilla.org/en-US/questions/1362295 and right-click on the Firefox logo above your question title and choose "Save image as", it tries to save as a PNG file.

I've uploaded a screenshot at https://www.screencast.com/t/pv9PGsjjN5SU

Well, I would but one of the sites is a little personal... But maybe the same problem is effecting another site.

Go here: https://www.pchomeec.tw/ then well, ok I will select a product go here instead: https://24h.pchome.com.tw/prod/DCAKDH-A9009RJBX This is a product page found through search on the main site. When the new link opens the page is white. Nothing loads! Nothing! It's blank! I cannot see any product info. So I am wondering if the same problem is happening here, and this is more serious product than the saving photo issue. But I will consider sending you that link later after we fix this one above first.

Thanks.

Hi Jeff, If I understand correctly, you said that the problem of images not loaded started when you set image.avif.enabled to False. Please reset that preference back to the default. There's a reset button to the far-right of the preference row.

By the way, I bought a Herman Miller Aeron last year at the beginning of the pandemic. It's been great. ☺️

Hi Jeff, browsers send an "Accept" header specifying supported content types with each request. By default, recent versions of Firefox send this:

text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,*/*;q=0.8

As you can see, it informs sites that AVIF and WEBP are supported.

Do you want to try my add-on that edits the Accept header on the fly to strip out either or both of those formats? That discourages sites from substituting AVIF/WebP for JPEG/PNG, but doesn't literally block them if that's all there is.

Here's how:

(1) Keep the default settings in Firefox

(2) Install from https://addons.mozilla.org/firefox/addon/dont-accept-webp/

(3) After installing, click the extension's toolbar button and check the box to strip image/avif

Any difference?

Note that you can move the button to the Overflow drop-down list if you can't afford the toolbar space. Just right-click the button > Pin to Overflow Menu.

Hi Chris,

I already reset everything back when the photos would not load in the other website I was using. But no matter what I did pchome site still is not loading product pages.

The problem for pchome stuff is that that problem started on updating FF. Nothing to do about the AVIF stuff that I changed, because I put everything back already.

As for Herman Miller, hahahaha, I didn't buy one and won't, but glad you like it. I just picked something from the site. They are expensive, but I heard they are good. I have a dual back chair, I used it for 10 years, bought a new one earlier this year. I won't use anything else because it will not, no matter how hard you try, allow you to slouch. Herman miller I think you can still slouch right? I need something that forces me to sit up straight. L5/S1 issue....

Hi jscher, it seems our messages crossed last night and I missed yours.

So I installed the plug-in, no changes at all. Both websites are still acting the same way. Pictures from one are still being saved as AVIF, I checked to see if they converted on save, and they did not. And Pchome is still not loading product pages.

I am wondering if these two issues are separate issues and are not caused by the problem. Because it seems that Chris can open the pchome product page without any issues, but I cannot.

I have several blockers installed also. ublock origin, privacy badger and AdBlock. But I have shut them all off and the problem still exists. Before the update everything was working fine also.

I am wondering, should I reinstall FF to an earlier version? Can I downgrade or do I have to uninstall and install? I worry I will lose everything.

Sorry, I don't have any sites to test on.

In the process of searching for one, I discovered a couple "how to" blog posts suggesting to use a <picture> tag to offer Firefox multiple formats:

<picture>
  <source srcset="images/example.avif" type="image/avif">
  <source srcset="images/example.webp" type="image/webp">
  <img src="images/example.jpg" alt="description of example image">
</picture>

• https://www.finally.agency/blog/what-is-avif-image-format
• https://jakearchibald.com/2020/avif-has-landed/

If a site is doing that, changing the Accept header might not have any effect because Firefox can skip the JPEG image and choose the AVIF format instead. I haven't tried testing it.

Some other strategy would be needed, such as modifying the <picture> tag sources. But I don't know how complex that would be. If the image quality is acceptable with the AVIF file, you could use a converter. I have a different add-on for that; it works similarly to screenshotting the image:

https://addons.mozilla.org/firefox/addon/save-webp-as-png-or-jpeg/

For PCHome, have you tried "the usual"?

If a site is generally known to work in Firefox, these are standard suggestions to try when it stops working normally:

Double-check content blockers: Firefox's Tracking Protection feature, and extensions that counter ads and tracking, may break websites that embed third party content (meaning, from a secondary server).

(A) The shield icon toward the left end of the address bar usually turns a bit purplish when content is blocked. Click the icon to learn more or make an exception. See: Enhanced Tracking Protection in Firefox for desktop.

(B) Extensions such as Adblock Plus, Blur, Disconnect, DuckDuckGo Privacy Essentials, Ghostery, NoScript, Privacy Badger, uBlock Origin or uMatrix usually provide a toolbar button to manage blocked content in a page. There may or may not be a number on the icon indicating the number of blocked items; you sometimes need to click the button to see what's going on and test whether you need to make an exception for this site.

Cache and Cookies: When you have a problem with one particular site, a good "first thing to try" is clearing your Firefox cache and deleting your saved cookies for the site.

(1) Clear Firefox's Cache

See: How to clear the Firefox cache

If you have a large hard drive, this might take a few minutes.

(2) Remove the site's cookies (save any pending work first). While viewing a page on the site, click the lock icon at the left end of the address bar. After a moment, a "Clear Cookies and Site Data" button should appear at the bottom. Go ahead and click that.

In the dialog that opens, you will see one or more matches to the current address so you can remove the site's cookies individually without affecting other sites.

Then try reloading the page. Does that help?

Testing in Firefox's Safe/Troubleshoot Mode: In this mode, Firefox temporarily deactivates extensions, hardware acceleration, any userChrome.css/userContent.css files, and some other advanced features to help you assess whether these are causing the problem.

If Firefox is running:

You can restart Firefox in Safe/Troubleshoot Mode using either:

• "3-bar" menu button > Help > Troubleshoot Mode... (before Fx88: Restart with Add-ons Disabled)
• (menu bar) Help menu > Troubleshoot Mode... (before Fx88: Restart with Add-ons Disabled)

and OK the restart. A small dialog should appear. Click the Open button (before Fx88: "Start in Safe Mode" button).

If Firefox is not running:

Hold down the Shift key when starting Firefox. (On Mac, hold down the option/alt key instead of the Shift key.) A small dialog should appear. Click the Open button (before Fx88: "Start in Safe Mode" button).

Note: Don't use the Refresh without first reviewing this article to understand what will be deleted: Refresh Firefox - reset add-ons and settings.

Any improvement?

Can you post a link to a publicly accessible page (i.e. no authentication or signing on required)?