CSS3 動畫效果-淡入淡出

a img {
-webkit-transition: all 1.7s cubic-bezier(0.230, 1.000, 0.320, 1.000); 
transition: all 1.7s cubic-bezier(0.230, 1.000, 0.320, 1.000);
}

a:hover img{
-webkit-transition: all 1.7s cubic-bezier(0.230, 1.000, 0.320, 1.000); 
transition: all 1.7s cubic-bezier(0.230, 1.000, 0.320, 1.000);
}