         # we have to extract a background url into a temporary IMG
         # element so that it can be processed by colorThief
 
-        url = el.style['background-image']
+        url = $(el).css('background-image')
                 .replace(/^url\(["']?/, '').replace(/["']?\)$/, '')
       else 
         url = el.src

            b: rgb[2]
          hsl = rgb_to_hsl rgb
          color = {rgb, hsl} 
          console.log color
          callback color if callback
          return color
        else 
          console.log "timeout"
          setTimeout imagePoll, 50
          return null


    skip_element = (behind_el && $(behind_el).has($(el)).length > 0) ||
                    (!is_image && rgb.a == 0)

    if skip_element
      hidden_els.push [el, el.style.visibility]
      el.style.visibility = 'hidden'
