#copyurlsexpert-toolbar-btnmain {
  list-style-image: url(chrome://copy-urls-expert/skin/cue-icon16.png);
}

#copyurlsexpert-toolbar-btnmain {
  list-style-image: url(chrome://copy-urls-expert/skin/cue-icon16.png);
}

/* Inside customization panel, use a 32x32 image (FF 29+)*/
.customization-palette #copyurlsexpert-toolbar-btnmain {
  list-style-image: url(chrome://copy-urls-expert/skin/cue-icon.png);
}

Fix blurry icon in customization panel FF29+
Fix blurry icon in customization panel FF29+
