Because the station doesn’t provide artwork in the stream metadata?

Try NDR 1 stations.... 

I don’t know what the second screenshot is from, but I guess Sonos either uses a different API or simply doesn’t dig out the artwork. 

The second screenshot is from logitech Media Server using a stream url from TuneIn.  The Sonos image is also a TuneIn link.

I added a station using the same url from logitech - just shows a default black music image.

Radio Paradise streams do show album art.

Given that Sonos disclaim any involvement in how music services actually work, I guess it's just something else to put up with... But I think it does show how clunky and antiquated the S2 interface and features really are.

It's almost as if nobody really cares.  Probably legal battles with Google et al. are evidently more important. 

Radio Paradise via TuneIn -- which I can no longer get from the UK owing to licensing issues -- or using their own service? Obviously with RP’s own installed service on Sonos it works in full.

RP service works but haven't tried radio paradise via TuneIn... Guess it won't have art.