Generally, if there are no images being displayed for a particular artist we were unable to locate a usable picture of the artist. This is more common on channels that do not play current music. Please note, deceased and living artists that have not released a single or album recently or are not actively promoting their music, also may not have photos displayed due to our inability to locate a usable artist image.

Related

How do I let you know that the information on the screen is incorrect?
Why doesn’t the music information on the screen always match with the artist whose song is being played?
Where is the music information on the screen coming from?