I suspect this was an oversight in the latest update, but the album cover is now tiny in full-screen mode, making room for the background on the artist's profile instead. There seems to be no way to maximize the album cover, which I'd rather be looking at. I'd like that option back!
Thanks for bringing us your feedback in the Spotify Idea Exchange.
Your suggestion has gathered the votes necessary and your feedback is now reaching the internal teams at Spotify. They're aware of the vote count and popularity of this idea. We'll continue to monitor and check out the comments here, too.
As soon as we have any updates on its status, we'll let you know.
More info on how your feedback reaches Spotify via the Idea Exchange can be found here.