The art in question (a drawing of Madonna with a black eye) has been used for the cover of a 7″, thousands of t-shirts and was proposed for the cover of their album (which was refused by their distribution company). They have yet to pay Brown for the use of this image.
Crystal Castles say that they have paid the artist and amended the initial contract. Brown’s account is only his side. Please read this to see the other side of the story.