The thing is that I'm pretty sure, like almost a hundred percent certain, that I saw the album art showing up in the notification center, when I began using the "now playing"-widget. But then it suddenly disappeared, and got replaced by the spotify logo itself to indicate that it was the current program that was using the media keys/widget. So that's why I find this situation so weird. Would also apprechiate a fix/update for this, spotify.
I can relate. I believe it was about a year ago, when I began using the "Now Playing"-widget in the notification center on my MacBook Air (Early 2015). The very first song I played, viewed the artwork for the song. But when I skipped track, it got replaced with the Spotify logo. Just like you. It never worked again, and I find it cheap looking. So I'd really prefer if there could be an update to fix this small issue.
Thanks for making this suggestion in the Community 🙂
The best way to pass on feedback like this to Spotify is by creating an idea in the Idea Exchange - just head here to do so.
That way, other users will be able to vote for it, and Spotify will be able to get a sense of how important this is to the Spotify Community. If the idea gets enough votes, then Spotify will consider implementing it!
Hope that helps! Let us know if there's anything else we can help you with 🙂