'Lookup the images for the given URIs.
The default implementation will simply call :meth:`lookup` and
try and use the album art for any tracks returned. Most local
libraries should replace this with something smarter or simply
return an empty dictionary.
:param list uris: list of URIs to find images for
:rtype: {uri: tuple of :class:`mopidy.models.Image`}'

def get_images(self, uris):

    result = {}
    for uri in uris:
        image_uris = set()
        tracks = self.lookup(uri)
        if isinstance(tracks, models.Track):
            tracks = [tracks]
        for track in tracks:
            if (track.album and track.album.images):
                image_uris.update(track.album.images)
        result[uri] = [models.Image(uri=u) for u in image_uris]
    return result
