I assume you mean the game is no longer in you library. The ritual question to ask is: did you buy the game from GOG, or a key from some key reseller site?

More questions...
- Where? Galaxy client or web browser?
- What? Is just the "logo" / title image missing or is there no game entry at all anymore?
- Tried to use the search function / name filter in the library?

For the web library : logo / game are still there (checked).. i don't use the client so ....i don't now if you mean if it's "just" the logo which is missing or the game too.

Account wide : go under "order & settings" (top of screen - in the menu with your username - with a browser) and type the title of the game (or part of it) in the search bar... if the game is still there if not back to Breja question.

You could use the filter option as mentioned in library too and also "maybe" you have hidden the title by mistake -> i dont know.

Or maybe the question is literally about the cover not loading in library? In which case it may just be a temporary CDN issue.

I post a Screenshot

Yeah, probably a minor CDN issue, happens sometimes, and even more likely now, considering the recent problems. Give it some time.

Its been like this for 1-2 Weeks or more.

It's a bit more specific : i took a screenshot about this one (web library) : looks like much more tied with the client ONLY.

I agree with Cavalary though...since the issue encountered by GOG matches with the time frame you mention.

Here's a link to the missing boxart.
https://images.gog-statics.com/246dbf122e5700f6fd9128c68ba202b65643968735afc39fa3fbe983ae316c51.jpg

Save it anywhere drag the pic onto the missing blank spot (where it says "Bild konnte nicht geladen werden"). As far as I remember Galaxy is saving this information after you've done this.

Edit: I also just installed it myself using Galaxy and for me the boxart is working fine. So reinstalling might help as well.

Works fine for me too and I'm stuck on some 6 months old build of Galaxy (2.0.57.14 - Beta, January 24th).

its still not fixed for me.

A friend of mine just showed me a post that might help you:
https://www.gog.com/forum/general_beta_gog_galaxy_2.0/greyed_out_images_on_galaxy_library/post3

Defiance had been back working but this time Cyberpunk didnt "work". so i tried the .bat file in that link and now i have this:

those 2 things are gone now. i hope this .bat file was "safe"...