.wp_themeSkin span.mce_embedpluswiz, span.mce_embedpluswiz
{
    background: transparent url("https://d27a7eb51b9b7c04a312-0b273fd55ee1eed53252d435e774be47.ssl.cf2.rackcdn.com/btn_embedpluswizoff_png-1347020734") no-repeat scroll center center !important;
}

.wp_themeSkin span.mce_embedpluswiz:hover, span.mce_embedpluswiz:hover
{
    background-image: url("https://d27a7eb51b9b7c04a312-0b273fd55ee1eed53252d435e774be47.ssl.cf2.rackcdn.com/btn_embedpluswiz_png-1347020735") !important;
}