Use `image-url` for chosen sprite
Use `image-url` for chosen sprite

Ensure the stylesheet includes the correct asset path when assets are
compiled.

robinwhittleton/whitehall,YOTOV-LIMITED/whitehall,askl56/whitehall,hotvulcan/whitehall,ggoral/whitehall,ggoral/whitehall,robinwhittleton/whitehall,YOTOV-LIMITED/whitehall,YOTOV-LIMITED/whitehall,ggoral/whitehall,YOTOV-LIMITED/whitehall,hotvulcan/whitehall,askl56/whitehall,hotvulcan/whitehall,ggoral/whitehall,robinwhittleton/whitehall,alphagov/whitehall,alphagov/whitehall,askl56/whitehall,askl56/whitehall,alphagov/whitehall,hotvulcan/whitehall,alphagov/whitehall,robinwhittleton/whitehall