Yes, it's fixed. Thank you.

Glad to hear this. You're welcome. :)

Well then, looks like there's nothing left for me to do. Good job, everyone!

The recent fix started showing the Cyberpunk 2077 Legacy cover I provided, using the Inspect Element Product ID, i provided

Cyberpunk 2077
gog-account-product="1423049311"

Cyberpunk Image provided
Cyberpunk 2077 - Cover.PNG

Today the Legacy cover disappeared, and after checking Inspect Element, I found the Product ID is unchanged.
This time it's the image link at fault, I get a 404 Not Found error when trying to view the link manually

https://gog.bigpizzapies.com/legacy_covers/1423049311.jpg

Seems to only be this image that's disappeared, from my library.

While I'm posting.
Not how I did it, which is a one click and done method.

In the Library, just right click on the missing image, and select inspect element
Cyberpunk 2077 - Context Menu - Imgur Image Link

This opens inspect element, on the middle highlighted line in this image
Cyberpunk 2077 - Inspect Element - Imgur Image Link Click on this image for the full size view.
The first of the Indented lines in the section is where, I find the Product ID, which the cursor is pointing to in the image.

No searching required, just right click and look for
gog-account-product=

"Look for" is basically the same as searching. Using the search function it simply is a bit easier to find trhe string you are looking for.
Plague Tale disappeared as well yesterday but I already replaced it with the image from the GOG API.
I reuploaded the Cyberpunk pic - let me know if it is fixed and if it stays fixed.

Fair enough for the search part, but I find just looking quicker.
Still no need to click on the game first, just Right click on image location
The advantages of my method
One click less
Opens on the currently used image link, which in the recent Cyberpunk case, was the issue.

Regarding which, I can confirm the Cyberpunk pics back in my library.

That's the only thing that really matters :)
Let me know if this should change.

Plague Tale boxart is gone again ... is Cyberpunk gone again as well?

yes, I have both missing again

Thanks. alaliabooks informed me about a possible solution (convert them to jpg). I will do so and upload both pics again today.

Edit: Uploaded once again. Please let me know if it should disappear again.

A plague tales back, but not Cyberpunk

I see it's listed as a JPG
title="Cyberpunk 2077" srcset="https://gog.bigpizzapies.com/legacy_covers/1423049311.jpg"
Product ID remains the same
gog-account-product="1423049311"

I've no idea why it's not showing up now, when it was before
Here's a pic of everything under the CyberPunk 2077 Inspect element section.
Cyberpunk 2077 - ProductID=1423049311 - Inspect Element.PNG

{EDIT} getting a 404 not found for the image link again.

That got it back, let's hope it stays put now.

Maybe we should use some kind of digital glue? :D

Does Adalia Fundamentals not work anymore with Greasemonkey on newer Firefox versions?

I've upgraded Firefox and Greasemonkey a few week ago (FF 68, GM 4.9). Since the upgrade AF seems not to work anymore. I neither have an entry in the about menu nor do I see the MaGog links on the game cards. Greasemonkey tells me AF is version is 1.9.2 and that no newer version is available. Barefoot Essentials still is working after the upgrade.