Would anybody be so kind and post the complete name of _glx_vertical_cover.webp and _glx_bg_top_padding_7.webp
You can find them in your C:\ProgramData\GOG.com\Galaxy\webcache folder in a subfolder.

It realy bugs me that I can't even edit the missing media. I have the correct thumbnails, but they won't work because I doNÄt have the file name.

If anybody has another solution to enable thumbnai media editing when there is no thumbnail nin the folder I would appreciate it. Thanks!