These are the CSS attr's they accept

  ["background", "border", "color", "font", "line", "margin", "padding", "text", "-webkit-background", "-webkit-border", "-webkit-font", "-webkit-margin", "-webkit-padding", "-webkit-text"]

Try this:

  console.log("%c ", 'background: url("http://placekitten.com/200/200"); padding: 5000px')

edit: put my code snippets in code blocks