FW: Rhythmbox Coverart Plugin Never Finds Images

> > -----Original Message-----
> > From: Jonathan Matthew [mailto:[email protected]]
> > Sent: Friday, 07 September, 2012 12:32
> > To: John Frankish
> > Cc: [email protected]
> > Subject: Re: [Rhythmbox-devel] Rhythmbox Coverart Plugin Never Finds 
> > Images
> >
> > On Fri, Sep 7, 2012 at 5:27 PM, John Frankish <[email protected]> wrote:
> > Hi,
> >
> > No matter which track is playing (see an example below), the 
> > coverart
> > plugin never seems to fetch any cover art.
> >
> > In this case it was because last.fm doesn't have a cover image for this album.
> > Try something less obscure?
>
> I've tried something like 50 tracks, some of which were far from obscure, and the result is the same.
>
> "rhythmbox-missing-artwork.svg" displays, but is something required in mimeapps.list to fetch and display cover art perhaps?

To add to this, I tried:

$ gvfs-open "http://ws.audioscrobbler.com/2.0/?method=album.getinfo&artist=U2&album=The+Joshua+Tree&api_key=ff56d530598d65c1a4088e57da7be2f9"

..which gave:

The Joshua Tree U2 1412230 026312fe-cec5-3ea8-9408-3ebc665b6985 http://www.last.fm/music/U2/The+Joshua+Tree 20 Nov 2007, 00:00 http://userserve-ak.last.fm/serve/34s/12640013.png http://userserve-ak.last.fm/serve/64s/12640013.png http://userserve-ak.last.fm/serve/174s/12640013.png http://userserve-ak.last.fm/serve/300x300/12640013.png http://userserve-ak.last.fm/serve/_/12640013/The+Joshua+Tree+the+mostknown+cover+of+The+Jos.png 629848 6660723 Where The Streets Have No Name (Album Version - Remastered) 336 http://www.last.fm/music/U2/_/Where+The+Streets+Have+No+Name+(Album+Version+-+Remastered) 0 U2 704acdbb-1415-4782-b0b6-0596b8c55e46 http://www.last.fm/music/U2 I Still Haven't Found What I'm Looking For (Remastered) 277 http://www.last.fm/music/U2/_/I+Still+Haven%27t+Found+What+I%27m+Look
 ing+For+(Remastered) 0 U2 704acdbb-1415-4782-b0b6-0596b8c55e46
...

Both the url below show an image in a browser

http://userserve-ak.last.fm/serve/34s/12640013.png
http://userserve-ak.last.fm/serve/_/12640013/The+Joshua+Tree+the+mostknown+cover+of+The+Jos.png

..and if I copy a track locally and download one of the above images and rename it cover.png, it is displayed when the track is played by rhythmbox.

Is the coverart plugin unable to parse the above maybe?