how to delete artist picture(pic next to artist name) from iPhone

I want to delete the artist picture from my iPhone. I don't know how it come. I think it come with the song I download so I try delete that song and download a different song by the same artist but the artist picture is still there. I want to delete it. Does anyone know how to?help please. (I'm using ios7 and iTunes 11)

(I think the picture is in my iphone(I am not sure) but I can't find it)