As in the title, I have set up around 50 custom cover images and one day, just like that - every single custom cover just disappeared. They didn't go back to default or back to no image at all with a font title and gradient background but just turned into blank-grey rectangles. Please see screenshot attached.

Now, when clicked on media and trying to edit the cover a message "Could not load the image" appears and I can't click on it anymore to re-upload the image.

So it just stays like that, anyone had the same problem? Any solution is known maybe before I reinstall the whole thing again and will be forced (if reinstall even helps) to sync and customise the whole thing again.

Thanks

Reinstall Galaxy, fixed it for me.

Reinstalling GOG Galaxy is completely unacceptable.

Adding my voice to this.
I have a number of titles where this happens. Mostly indie titles at that.

I've found the default repository for tiles, icons and backgrounds in the installation files for GOG Galaxy 2.0, but the games are by registry code (Steam ID, as an example) and the images have alphanumeric strings as file names.
C:\ProgramData\GOG.com\Galaxy\webcache\46988377406622883\steam\1151120 for Arrest of a Stone Buddha, as an example, where the tile is glitching. Only the icon is in the folder, c92faa69f042e59e6f9bc6a7426021b58fdd8841ab7310054fd6ea3039457470_glx_square_icon_v2.

It'd be great if GOG could at least provide access to a repository of tiles so we could manually download replacements if there's a glitch.

same problem for me

it appears also on a new installation on new computer

I think that appears, when there is a problem with the custom image in the cloud. I have the same for two games, where I changed the image. I can't change it on another computer as well. After disconnecting and connecting again (with Steam) I could change the image, but then the same problem happened again. Changing / adding the image in the installation folder (as mentioned above) also doesn't work, so I think it must be saved in the cloud. But we don't have direct access to it, do we?